A frequent question among people of a certain age, including yours truly, is “Why, when I weigh the same as or less than I did when I was younger, does my waist keep getting bigger?” Phrased another way, the question could be “Why, when my body mass index has not changed, am I fatter than I used to be?”
The simple answer is that the index, usually called B.M.I. for short, is a crude measure of fatness in individuals. Calculated by dividing one’s weight in kilograms by the square of one’s height in meters, it doesn’t differentiate between fatty and lean tissue.
“The B.M.I. tables are excellent for identifying obesity and body fat in large populations, but they are far less reliable for determining fatness in individuals,” explained Dr. Carl Lavie, a cardiologist at the Ochsner Heart and Vascular Institute in New Orleans.
Fat Tissue, Lean Tissue
Fat takes up about four times the space of muscle tissue, for example, so it is quite possible to look and feel fatter even if your height and weight remain the same. This is particularly common among women past 50 and men past 60, and the results are likely to show around the middle.
For children and the elderly, body mass values can be especially misleading because the relationship of lean body mass to height changes as they get older.
B.M.I. charts pop up all over the place, in popular publications, exercise facilities and doctors’ offices. The charts are widely used by doctors to determine if their patients are underweight, normal weight, overweight or obese. Thus, a body mass of less than 18.5 is considered underweight; 18.5 to 24.9 is considered a healthy weight; 25 to 29.9 is overweight; 30 to 39.9 is obese; and 40 or more is morbidly obese.
If you fall into the “healthy weight” or “underweight” range, you can easily be lulled into a false sense of security. But thinness is not necessarily healthy — recall the 97-pound weakling from the Charles Atlas ads of yore. A low B.M.I. could be indicative of malnutrition, anorexia, cancer or a wasting disease. On the other hand, if you are an athlete or body builder, your B.M.I. could mistakenly put you in the range for overweight or obese.
Degree of body fatness is a better way than body mass to classify individuals. Both the World Health Organization and the National Institutes of Health define obesity as more than 25 percent body fat in men and more than 35 percent body fat in women. So “a woman who is 5 feet 5 inches tall and weighs 120 to 125 pounds could be quite fat,” Dr. Lavie told me, “even though her weight and B.M.I. seem O.K.”
Among Americans in general, he said, “a six-foot, 250-pound man will be obese, but if he were an N.F.L. lineman of 6-foot-3 weighing 280 pounds, he might be solid muscle with only 2 percent body fat.”
The Obesity Paradox
Of course, most Americans with a body mass index in the overweight or obese range carry around too much fat in relation to muscle. And a study that followed 527,265 American men and women ages 50 to 71 in 1995-96 found that those rated overweight based on a body mass reading of 25 to 29.9 were 20 to 40 percent more likely to die within 10 years, and those rated obese, at 30 or higher, were two to three times as likely to die within a decade as those who had a lower reading in midlife.
In an editorial in the July issue of Mayo Clinic Proceedings, Dr. Lavie and colleagues discussed what has been termed the “obesity paradox” among patients with heart failure. The paradox refers to the repeated finding that while overweight people are more prone to heart failure, patients with heart failure have lower mortality rates if they are obese. The reason for this paradox is far from clear, though Dr. Lavie suggested that one explanation could be that once people become ill, having more bodily “reserve” could be to their advantage.
The editorial was prepared in response to a report in the same journal by Antigone Oreopoulos of the University of Alberta and her colleagues. The authors compared the B.M.I. of 140 heart failure patients with a more accurate, though more involved, measure of fat and lean body mass using a DEXA scan (DEXA stands for dual energy X-ray absorptiometry). They found that B.M.I. value alone misclassified the degree of body fatness in 41 percent of the patients.
Their conclusion: Having more lean tissue and less fat may more accurately predict a patient’s survival chances. Thus, among patients with heart failure, these authors stated, “body mass index may not be a good indicator of adiposity.”
Dr. Lavie and coauthors wrote, “Although B.M.I. is the most common method to define overweightness and obesity in both epidemiological studies and major clinical trials, clearly this method does not necessarily reflect true body fatness, and B.M.I./body fatness may differ considerably among people of different age, race and sex.”
What to Measure
A more reliable, but still relatively simple, assessment of fatness would rely on a skin-fold score based on measurements taken with a caliper at several areas (in men, the thigh, midchest and abdomen, and in women, the thigh, triceps and area above the hip bone) that reflects the amount of fat under the skin.
Or, since abdominal fat is more hazardous, simply take a tape measure around the widest part of the abdomen and another at the hips and calculate the waist-to-hip ratio. For men it should be no higher than 0.90, and for women no higher than 0.83.
An oversize abdomen is symptomatic of too much metabolically active visceral fat, which increases the risk of heart attack and premature death. If just waist measurements are used, Dr. Lavie said, a man’s waist should be less than 40 inches and a woman’s less than 35.
Exercise is the best way to minimize an age-related rise in body fat, the doctor said. Aerobic exercise, though important at all ages, is not enough. You must also do weight training to build and maintain muscle. And since the body’s production of testosterone, the hormone that favors muscle-building, diminishes with age in both men and women, you may have to increase the amount of strengthening exercises as you get older just to stay in place.
Fresh Concerns on How Diet and Medicines Interact, From Pepper to PomegranateAmericans increasingly view the food they eat as medicine to help lower cholesterol, reduce high blood pressure and control blood sugar. But as with prescribed drugs, the health-improving qualities of foods such as olive oil, nuts and fruit can interact with other medications, causing possible problems.
Pharmacists often warn people not to mix anti-cholesterol drugs known as statins with grapefruit juice. Newer research suggests that other fruit juices, including cranberry and pomegranate, as well as olive oil may also interfere with how statins work in the body. Other laboratory studies show that certain popular teas can block the effect of some medications, including the flu drug Tamiflu. And switching to a low-fat diet, itself a healthy lifestyle change, could reduce the potency of some medications.
http://online.wsj.com/article/SB10001424052748704256304575320743052254682.html?KEYWORDS=shirley+s+wang#articleTabs%3DarticleWhen ingested, ginger can help to relieve muscle pain.
Caveat: By the second day after the exercise, the differences in pain between the test groups were statistically insignificant.
THE FACTS
Cooking meat at high temperatures is known to create toxins called heterocyclic amines, which have been linked to some cancers. Marinating lowers the risk by preventing the formation of the toxins. But one ingredient that makes a big difference is rosemary. Studies show that adding it to ground beef and other types of muscle meat before grilling, frying, broiling or barbecuing significantly reduces heterocyclic amines.
In a study published in The Journal of Food Science in March, scientists tested extracts of rosemary on ground beef patties that were cooked at temperatures from 375 degrees to 400 degrees Fahrenheit. The extract was added to both sides of the meat before cooking. The higher the concentration, the greater the reduction in heterocyclic amines (in some cases by over 90 percent.
Scientists attribute this to specific antioxidants in rosemary: rosmarinic acid, carnosol and carnosic acid. Another study two years ago compared several marinades and found that the one that was most protective was a Caribbean mixture, which, they wrote, “contained considerable amounts” of the same three antioxidants.
If rosemary is not your thing, or you have an allergy, try marinades with garlic, onion and lemon juice. They have also been shown in studies to be effective (garlic and onion much more so than lemon juice).
THE BOTTOM LINE
Studies show that marinades with rosemary help eliminate some carcinogens in grilled meat.
They say you can never be too rich or too thin. But is it possible to eat too many leafy green vegetables?
Last year, an 88-year-old woman was admitted to NYU Langone Medical Center in a nearly comatose state, unable to walk or swallow and barely able to breathe. Though she had no history of thyroid disease, she was given a diagnosis of myxedema coma a life-threatening condition caused by extreme hypothyroidism, or low thyroid function.
The culprit, it turned out, was raw bok choy. The patient had been eating two to three pounds of it every day for several months, in the belief it would help control her diabetes. Instead, the vegetables may have suppressed her thyroid, according to NYU physicians who described the case in a letter in the May 20 issue of The New England Journal of Medicine.
Bok choy contains compounds called glucosinolates that have been found to inhibit thyroid function in animals.
“I don’t want to say people shouldn’t be eating raw vegetables, but everything in moderation — even things that are good for us,” said Dr. Michael Chu, an NYU resident physician who was one of the letter’s authors. “This probably wouldn’t have happened if the vegetables were cooked.”
Blueberry extract slows the spread of a difficult-to-treat form of breast cancer, according to a small study of mice in Cancer Research. So-called triple-negative breast cancers, which account for 10% to 15% of all breast-cancer cases, lack the three receptors that most cancer drugs target. In a preliminary test-tube experiment, researchers discovered that blueberry extract, compared with other fruit and vegetable extracts, had the greatest effect on these tumors without harming healthy cells. The researchers randomized 16 mice to receive either blueberry extract—a daily dose of unadulterated juice extracted from blueberries that was roughly equivalent to five ounces of blueberries a day for a 150-pound person—or a placebo. One week after the first dose, the mice were injected with triple-negative breast-cancer cells. Six weeks after that, necropsies revealed that the tumors of blueberry-fed mice were about 70% smaller than those in placebo-fed mice. The tumors of the blueberry-fed mice also had less potential to spread to other parts of the body.
• Emotional Memory: Emotions can outlast the memory of the facts on which those feelings are based, according to a study of amnesiac patients in Proceedings of the National Academy of Sciences. Five patients with severe anterograde amnesia, which largely prevents the creation of new memories, watched a 19-minute video of film clips about death and loss. (The clips included scenes from "Sophie's Choice" and "Forrest Gump.") Several times during the study, researchers asked the subjects how they felt. Five to 10 minutes after the final scene, the amnesiacs remembered nearly nothing they had seen. They were asked to rate their emotions on several scales, including to what degrees they felt happy, sad, amused and "bad/unpleasant" versus "good/pleasant". The responses showed that the amnesiacs' negative emotions were stronger and lasted longer, than a control group of subjects who had no brain damage. The researchers repeated the experiment with humorous film clips, finding that positive emotions also outlasted specific memories. The results contradict the popular concept that "erasing" painful memories can ease the distress associated with those memories, the researchers said
Caveat: Larger studies are needed to confirm the findings. It's unclear whether emotions are equally persistent among people with other forms memory loss, such as Alzheimer's.
Read the Study: Sustained experience of emotion after loss of memory in patients with amnesia
• Pregnancy: Weight-reduction surgery appeared to reduce obese women's odds for blood-pressure disorders during future pregnancies, according to a study in BMJ. Obesity is a major risk factor for pregnancy-related hypertensive disorders, which can cause low birth weight and premature birth, as well as increase the mother's risk for cardiovascular and kidney diseases. Researchers examined insurance claims from 585 U.S. women who had weight-loss surgery and gave birth within a four-year window. About half of the women underwent the surgery before giving birth, with an average of two years between the two events. Fewer than 10% of these women experienced pre-eclampsia (a sudden spike in blood pressure and in protein in the urine) and other hypertensive disorders during pregnancy, while these complications occurred in 31% of women who delivered before weight-reduction surgery. Women who delivered pre-surgery were twice as likely to develop gestational diabetes, which may lead to Type 2 diabetes later in life.
Caveat: Researchers relied on insurance claims and didn't have access to the mothers' height, weight or blood pressure. They also were unable to link the data on mothers to their infants' health.
Read the Study: Impact of bariatric surgery on hypertensive disorders in pregnancy: retrospective analysis of insurance claims data;
• Immune Responses: Visual signs of disease, independent of physical proximity, appear to jump-start our immune systems, according to a study in Psychological Science. Researchers took blood samples from 28 subjects before and after they watched a 10-minute slide show depicting photographs of furniture, a neutral subject. Later, the researchers divided the same subjects into two groups; one watched a slide show of visible disease symptoms—including pictures of people sneezing or infected with skin lesions—while the other group saw photographs of guns. The white blood cells of participants in the first group produced nearly 24% more interleukin-6, a protein used to judge immune response, after seeing the photographs of disease. There was no statistically significant increase, however, in interleukin-6 after the furniture or gun slide shows.
Caveat: The study was small. It's unclear what effect these cues have in a non-laboratory setting, or in relation to other sensory signals.
• Emergency Care: Uninsured patients who have a heart attack, despite being guaranteed treatment, take significantly longer to arrive at the hospital than insured patients, according to a study in JAMA. Greater delays between a heart attack and hospital treatment decrease the odds of survival, previous studies have shown. Researchers in this study examined the medical records of 3,721 heart attack patients at 24 U.S. hospitals, and then interviewed them about their insurance status and financial concerns. One-fifth of all participants were uninsured. Of those, more than 48% arrived at the hospital six hours or longer after the heart attack occurred, compared with 39% of insured patients without financial concerns about their coverage, and about 45% of insured patients with financial concerns. After adjusting for a host of factors such as age and disability, the researchers determined that delays were nearly 40% more likely among uninsured patients than among patients with insurance and no financial concerns.
Caveat: Traffic and geographic distance from the hospital likely affected these delays, but the researchers were unable to collect this data. The researchers also didn't determine whether lack of insurance was a factor in patients themselves delaying going to the ER. The study was conducted solely in urban areas, so the findings don't necessarily apply to other regions.
Read the Study: Health Care Insurance, Financial Concerns in Accessing Care, and Delays to Hospital Presentation in Acute Myocardial Infarction
• Sexually Transmitted Infections: Human papillomavirus, known for its link to cervical cancer and other tumors, appears also to increase the risk of HIV infection, according to a study in PLoS ONE. Researchers followed 2,040 HIV-negative Zimbabwean women for approximately two years. Every three months, the women were tested for HIV and 29 known strains of HPV. About one-quarter of the women had HPV at the beginning of the study. By the end of the study, 88 women (4.3%) developed HIV. But women who began with either of two particular HPV strains were twice as likely as other women to acquire HIV. Remarkably, women with the least persistent HPV infections were the most likely to get HIV. These findings suggests that the immune response to HPV—rather than abnormal cell growth—predisposes women to HIV infection, the researchers said.
Caveat: Unlike other strains of HPV, vaccines aren't available for the types associated with HIV infection. The researchers were unable to distinguish between biologically active HPV and inactive virus DNA deposited by a recent sexual partner.
• Migraines: Aspirin can provide adequate relief for many migraine sufferers who lack access to prescription medication, according to meta-analysis by the Cochrane Library. The authors analyzed results from 4,222 participants in 13 studies that compared the effectiveness of aspirin—alone or in tandem with a generic anti-nausea drug—with a placebo. Within two hours, one-gram doses of aspirin reduced the severity of migraine headaches in 52% of participants, while a placebo worked for only one-third of migraneurs. Aspirin also significantly reduced nausea and vomiting, which the addition of the anti-nausea drug further diminished.
Caveat: Frequent aspirin use can cause stomach and intestinal ulcers, and may contribute to hearing loss and other symptoms. As with all meta-analyses, the underlying studies have their own limitations.
Read the Study: Aspirin with or without an antiemetic for acute migraine headaches in adults
• Digestion: An intestinal bacterium apparently abundant among Japanese has evolved to improve the digestion of seaweed, according to a study in Nature. The human gut harbors trillions of bacteria, many of which help digest molecules that human enzymes cannot. Researchers identified a new class of enzyme that breaks down porphyran, a carbohydrate found exclusively in red algae. They then tested intestinal bacteria samples from 13 Japanese volunteers and 18 North American volunteers for the genetic sequence that creates the porphyran-breaking enzyme. The gene was common in the Japanese samples, but entirely absent from the North American samples. This string of DNA likely migrated from marine microbes to intestinal bacteria, though it's difficult to estimate when this happened, the researchers said.
More research backing up the cholesterol-lowering benefits of eating nuts indicates that for most people, consuming two handfuls of nuts a day appears to work better than one.
The findings apply to tree nuts such as walnuts, almonds, pistachios, macadamias, hazelnuts and peanuts.
Although peanuts actually belong to the legume family, they are considered to have many of the same nutritional components as walnuts, almonds and other tree nuts.
Researchers found that, for the average person, about two servings of tree nuts did a better job of reducing blood cholesterol and triglycerides than one serving. Researchers who examined the results of 25 previous studies on the health effects of nut consumption found a dose-related improvement in participants' blood-lipid levels.
The results are published this week in the Archives of Internal Medicine.
The lead author of the latest research, Joan Sabaté, says the study "confirms that nuts, indeed, lower cholesterol." A professor and the chairman of the department of nutrition at Loma Linda University, in Loma Linda, Calif., Dr. Sabaté was among the group of researchers that first linked nut consumption to a lower risk of heart attack several years ago.
That finding and others led the Food and Drug Administration in 2003 to allow processors to state on labels that "eating 1.5 ounces per day of most nuts ... as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease."
Dr. Sabaté said the research indicated that for the average person, a slightly higher amount of nuts—about 2.4 ounces, or two servings—does a better job than one serving of lowering cholesterol and triglycerides, another type of fat in the blood.
Still, he said, "we do not need many to get the benefit." One serving of almonds is about eight nuts; a serving of smaller nuts such as peanuts is about 15 to 20 nuts.
Dr. Sabaté's analysis involved nearly 600 people with high or normal blood cholesterol levels. None of the study participants were taking cholesterol-lowering medications.
The analysis compared a control group with two groups assigned to consume two different quantities of nuts.
People in one of the nut groups consumed an average of 67 grams of nuts, or about 2.4 ounces, per day.
These people had an average reduction in total blood cholesterol concentration of 5.1%, and a reduction in low-density lipoprotein, or so-called LDL or "bad" cholesterol, of 7.4%.
For the people who consumed about 1.5 ounces of nuts, total cholesterol fell by 3.2%, while "bad" cholesterol fell by 4.9%—suggesting a dose-related response.
Those who consumed about one ounce daily of nuts, total cholesterol fell by 2.8% while LDL cholesterol fell by 4.2%.
Significantly, however, the drops in cholesterol weren't seen in people considered obese—a new finding.
More studies are needed to understand why nuts are less effective at lowering blood cholesterol concentration among obese people, the researchers said.
Dr. Sabaté said the biggest improvement in blood lipid levels were seen among people who started out with higher cholesterol levels, as well as among those who consumed a "Western" diet of high-fat meats, dairy products and refined grains, compared with people consuming a "Mediterranean" diet emphasizing whole grains, lots of fruits and vegetables, fish and relatively little red meat.
"For the general population consuming a Western diet, the incorporation of nuts into their daily diet will result in greater improvement of blood lipid levels than for individuals already following a healthy Mediterranean or low-fat diet," researchers wrote.
Of the 25 studies, about two-thirds of them involved almonds or walnuts. The other one-third of studies looked at either macadamia, pistachio, hazelnuts or peanuts. The studies didn't include pine nuts or Brazil nuts.
The study was funded by Loma Linda University in California and by the International Tree Nut Council Nutrition Research and Education Foundation, an international group that represents the tree nut industry.
An analysis of U.S. health data links children's attention-deficit disorder with exposure to common pesticides used on fruits and vegetables.
While the study couldn't prove that pesticides used in agriculture contribute to childhood learning problems, experts said the research is persuasive.
"I would take it quite seriously,'' said Virginia Rauh of Columbia University, who has studied prenatal exposure to pesticides and wasn't involved in the new study, published Monday in Pediatrics. More research will be needed to confirm the tie, she said.
Children may be especially prone to the health risks of pesticides because they are growing, and they may consume more pesticide residue than adults relative to their body weight.
Pesticides break down in the body into compounds that can be measured in urine. Almost universally, the study found detectable levels: The compounds turned up in the urine of 94% of the children.
Children with higher levels had increased chances of having ADHD, attention-deficit hyperactivity disorder, a common problem that causes students to have trouble in school. The children may have eaten food treated with pesticides, breathed pesticides in the air or swallowed them in their drinking water. The study didn't determine how they were exposed.
Experts said it's likely that children who don't live near farms are exposed through what they eat.
"Exposure is practically ubiquitous. We're all exposed,'' said the study's lead author, Maryse Bouchard, of the University of Montreal.
She said people can limit their exposure by eating organic produce. In one government report, frozen blueberries, strawberries and celery had more pesticide residue than other foods.
A 2008 Emory University study found that in children who switched to organically grown fruits and vegetables, urine levels of pesticide compounds dropped to undetectable or close-to-undetectable levels.
Because of the known dangers of pesticides in humans, the U.S. Environmental Protection Agency limits how much residue can stay on food.
But the new study shows it is possible that even tiny, allowable amounts of pesticide may affect brain chemistry, Dr. Rauh said.
Exact causes of the children's reported ADHD, though, are unclear. Any number of factors could have caused the symptoms, and the link with pesticides could be by chance.
The new findings are based on one-time urine samples in 1,139 children and interviews with their parents to determine which children had ADHD.
The children, ages 8 to 15 years old, took part in a government health survey from 2000 to 2004.
As reported by their parents, about 150 children in the study either showed the severe inattention, hyperactivity and impulsivity characteristic of ADHD, or were taking drugs to treat it.
The study dealt with one common type of pesticide called organophosphates. Levels of six pesticide compounds were measured.
For the most frequent compound detected, 20% of the children with above-average levels had ADHD. In children with no detectable amount in their urine, 10% had ADHD.
"This is a well conducted study,'' said Lynn Goldman of the Johns Hopkins Bloomberg School of Public Health and a former EPA administrator.
However, relying on one urine sample for each child, instead of multiple samples over time, wasn't ideal, Dr. Goldman said.
The study provides more evidence that the government should encourage farmers to switch to organic methods, said Margaret Reeves, senior scientist with the Pesticide Action Network, an advocacy group that has been working to end the use of many pesticides.
"It's unpardonable to allow this exposure to continue,'' Ms. Reeves said.
—Copyright 2010 Associated Press
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| DALLAS, July 25 -- Lipogenesis increased significantly when glucose was replaced with fructose on a gram-for-gram basis in energy drinks consumed by six healthy volunteers, researchers here found. Action Points
Conversion of fructose to lipid occurred quickly, usually within four hours after ingestion, Elizabeth Parks, Ph.D., of the University of Texas Southwestern Medical Center, and colleagues reported in the June issue of the Journal of Nutrition.
Moreover, consumption of a high-fructose drink for breakfast increased liver-mediated fat storage after lunch, the researchers said.
"Our study shows for the first time the surprising speed with which humans make body fat from fructose," said Dr. Park. "Once you start the process of fat synthesis from fructose, it's hard to slow it down."
The findings provide strong support for clinical guidelines that recommend limiting processed carbohydrates, which often contain high-fructose corn syrup, she added.
Studies involving controlled feeding have shown that fructose could increase serum triacylglycerol levels and maintain the increase throughout the day in healthy individuals and in patients with diabetes. Chronic elevation of triacylglycerol levels could lead to accumulation of atherogenic lipoprotein remnants, the authors said.
Replacement of glucose with fructose in a fat-containing breakfast drink has been shown to increase the four-hour appearance of the meal's fatty acids in VLDL, suggesting increased reesterification of breakfast fat in the liver, they continued.
So the authors hypothesized that a fructose-induced rise in lipogenesis in the morning would further increase triacylglycerol concentrations following lunch. They also sought to determine the lipogenic effects of two different doses of fructose in healthy, relatively lean individuals.
Four men and two women volunteered for the study. Their mean age was 28 and they had a mean body mass index of 24.3 and mean serum triacylglycerol level of 1.03 mmol/L.
On separate days, the volunteers consumed breakfast energy drinks sweetened with 100% glucose, a 50-50 mix of glucose and fructose, and a 25-75 mix of glucose and fructose. The volunteers ate a standardized lunch four hours after consuming the drink.
Lipogenesis was assessed by serial testing for four hours after breakfast, and postprandial lipemia was measured following the lunch meal.
The drink containing only glucose led to a peak fractional lipogenesis of 7.8%. In contrast, the 50-50 mix and the 25-75 mix more than doubled peak fractional lipogenesis (15.98% and 16.9%, respectively, P<0.02).>
Fructose consumption at breakfast induced a dramatic rise in postprandial lipemia after the lunch meal. Consumption of the fructose-containing drinks was associated with an increase in postprandial serum triacylglyerols of 11% to 29% compared with the glucose-only drink.
Concentrations of triacylglycerol-rich lipoproteins increased by 76% to 200% with the 50-50 and 25-75 mix of glucose and fructose.
"The message from this study is powerful because body fat synthesis was measured immediately after the sweet drinks were consumed," Dr. Parks said. "The carbohydrates came into the body as sugars, the liver took the molecules apart . . . and put them back together to build fats. All this happened within four hours after the fructose drink. As a result, when the next meal was eaten, the lunch fat was more likely to be stored than burned."
The message should not be misconstrued by people who are trying to lose weight, she continued. Specifically, they should not eliminate dietary fruits, which have high fructose concentrations.
Overeating and excess caloric consumption remain the principal drivers of weight gain and obesity, she concluded.
The biggest limitation of the study, the researchers acknowledged, is its small sample size. However, they said, the repeated measures design supports the notion that the differences were real and would be reproducible.
Another limitation is the fact that the drinks were consumed first thing in the morning when participants were in the fasting state. That could lead to an underestimation of lipogenesis.
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| Primary source: Journal of Nutrition Source reference: Parks EJ, et al "Dietary sugars stimulate fatty acid synthesis in adults" J Nutr 2008; 138: 1039-1046. |
To judge by recent headlines, coffee could be the latest health-food craze, right up there with broccoli and whole-wheat bread.
But don't think you'll be healthier graduating from a tall to a venti just yet. While there has been a splash of positive news about coffee lately, there may still be grounds for concern.
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Hector Sanchez for The Wall Street Journal Source: WSJ research
This month alone, an analysis in the Archives of Internal Medicine found that people who drink three to four cups of java a day are 25% less likely to develop Type 2 diabetes than those who drink fewer than two cups. And a study presented at an American Association for Cancer Research meeting found that men who drink at least six cups a day have a 60% lower risk of developing advanced prostate cancer than those who didn't drink any.
Earlier studies also linked coffee consumption with a lower risk of getting colon, mouth, throat, esophageal and endometrial cancers. People who drink coffee are also less likely to have cavities, gallstones, cirrhosis of the liver, Parkinson's disease and Alzheimer's disease, or to commit suicide, studies have found. Last year, researchers at Harvard University and the University of Madrid assessed data on more than 100,000 people over 20 years and concluded that the more coffee they drank, the less likely they were to die during that period from any cause.
But those studies come on the heels of older ones showing that coffee—particularly the caffeine it contains—raises blood pressure, heart rate and levels of homocysteine, an amino acid in blood that is associated with stroke and heart disease. Pregnant women who drink two or more cups of coffee a day have a higher rate of miscarriages and lower birth-weight babies; caffeine has also been linked to benign breast lumps and bone loss in elderly women. And, as many people can attest, coffee can also aggravate anxiety, irritability, heartburn and sleeplessness, which brings its own set of problems, including a higher risk of obesity. Yet it's just that invigorating buzz that other people love and think they can't get through the day without.
Why is there so much confusion about something that's so ubiquitous? After all, some 54% of American adults drink coffee regularly—an estimated 400 million cups per day—and coffee is the second most widely traded commodity in the world, after oil.
WSJ's health columnist Melinda Beck discusses new evidence that drinking coffee may help prevent diseases such as prostate cancer, Alzheimer's and diabetes.
For starters, the vast majority of coffee studies to date have been observational, in which researchers examine large sets of data over many years, looking for patterns in peoples' habits and their health.
But subjects don't always remember or report accurately on how much they drink. Cup sizes can range from 6 to 32 ounces; caffeine loads can vary from 75 to nearly 300 milligrams. Loading up with sugar, flavored syrup and whipped cream can turn a no-fat, almost no-calorie drink into the equivalent of an ice-cream soda.
Even carefully constructed observational studies that correct for such variables can only find correlations, not prove a cause-and-effect relationship. There may be other, hidden reasons why people who drink a lot of coffee have a lower risk of illness—such as jobs that provide a steady income and access to health care, exercise and healthier food. Conversely, "people who don't feel that healthy may be less likely to drink six cups of coffee a day. ... It's just a possibility," says Jim Lane, a psychophysiologist at Duke University Medical Center who has studied the effects of caffeine for more than 25 years.
Indeed, many studies from earlier decades that linked coffee drinking to a higher risk of cancer were apparently detecting related habits instead. Once researchers started adjusting for study subjects who also smoked cigarettes, the additional cancer risk disappeared.
"When I went to medical school, I was told that coffee was harmful. But in the '90s and this decade, it's become clear that if you do these studies correctly, coffee is protective in terms of public health," says Peter R. Martin, a professor of psychiatry and pharmacology at Vanderbilt University and director of the school's Institute for Coffee Studies, founded in 1999 with a grant from coffee-producing countries.
Still, many researchers believe that the only way to draw firm conclusions about something like coffee is through experimental trials in which some subjects are exposed to measured doses and others get a placebo, with other variables tightly controlled. When that's been done, says Duke's Dr. Lane, "the experimental studies and the [observational] studies are in very sharp disagreement about whether caffeine is healthy or not."
His own small, controlled studies have shown that caffeine—administered in precise doses in tablet form—raises blood pressure and blood-sugar levels after a meal in people who already have diabetes. Other studies have found that caffeine and stress combined can raise blood pressure even more significantly. "If you are a normally healthy person, that might not have any long-term effect," says Dr. Lane. "But there are some groups of people who are predisposed to get high blood pressure and heart disease and for them, caffeine might be harmful over time."
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Epidemiologists counter that such small studies don't mirror real-world conditions, and they can't examine the long-term risk of disease.
The prostate-cancer study, for example, compared the coffee-drinking habits of 50,000 men working in medical professions with their incidence of prostate cancer over 20 years, and also took into account family history of prostate cancer and how frequently they had screenings. Roughly 5,000 of the men developed prostate cancer during that period, including 846 cases of the most advanced and lethal kind. But the more cups of coffee the men drank, the less likely they were to be in that most lethal group. "You can't do a randomized controlled trial on men starting in their 20s and following them until they are old enough to get prostate cancer," says lead investigator Kathryn Wilson, a research fellow in epidemiology at Harvard School of Public Health. "For some of these questions, observational studies are the best we are going to get."
As for diabetes, at least 18 studies have found that drinking three or more cups of coffee a day is linked with a lower risk of developing the disease. The more such findings are repeated, particularly with different populations, the stronger the evidence is.
In both the prostate and diabetes studies, the health benefits were found for caffeinated as well as decaffeinated coffee, suggesting that some other component in coffee is responsible. Coffee contains traces of hundreds of substances, including potassium, magnesium and vitamin E, as well as chlorogenic acids that are thought to have antioxidant properties.These may protect against cell damage and inflammation that can be precursors to cancer, diabetes, neurological disorders and cardiovascular disease.
One theory gaining credence is that some of those beneficial components may counterbalance some of the harmful effects of caffeine. For example, while caffeine keeps people awake in part by blocking adenosine, a brain chemical that brings on sleep, the chlorogenic acid in coffee keeps adenosine circulating in the brain longer.
And while caffeine seems to boost adrenaline that primes the body for action, coffee itself may have a calming effect. Even the aroma of coffee beans can help ease stress in rats, researchers at Seoul National University in South Korea showed in a study in the Journal of Agricultural and Food Chemistry last year. Chlorogenic acid also slows the release of glucose into the bloodstream after a meal, which may counteract caffeine's glucose effect.
"It's a yin and yang effect," says Vanderbilt's Dr. Martin, an addiction psychiatrist who also notes that former alcoholics who drink coffee are more apt to stay sober than those who don't. Even though these studies are just associations, he says, "they may provide leads for us to better understand some of the most common illnesses that affect mankind as well as developing ways to treat them. But everything is cloaked in 'mays.' "
Most researchers agree that there isn't enough evidence about the benefits of coffee to encourage non-coffee drinkers to acquire the habit. And no one has come close to finding a recommended number of cups per day for optimum health. People's reactions to coffee are highly individual. One small cup can give one person the jitters while others can drink 10 cups and sleep all night.
At the same time, people who love coffee probably don't need to worry that they are harming their health by drinking it -- unless they already have high blood pressure or are pregnant or are having trouble sleeping, in which case it's prudent to cut down.
Even Dr. Lane, who thinks the risks of caffeine outweigh coffee's potential benefits, concedes he drinks several cups a day. "Why do I do it?" he muses. "I ask myself that question ..."
—Email healthjournal@wsj.com.Correction & Amplification:
Peter R. Martin, a professor at Vanderbilt University School of Medicine and director of the Institute for Coffee Studies there, is an addiction psychiatrist. An earlier version of this column incorrectly stated that he is an addiction psychologist.
Red wine has long been touted as a health elixir. Now wine's purported health-giving ingredient, resveratrol , is available in daily supplements, beverages and even a new nutritional bar claimed by sellers to help you live longer and help prevent cancer and other diseases. Until recently, the evidence for resveratrol has been animal data, but preliminary human testing has yielded intriguing results.
wsj, Dec 22, 209
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Tim Foley Resveratrol is a substance found in grapes and other plants. Many of the supplements on the market extract it from the Japanese knotweed plant, which is a plentiful and inexpensive source. Switzerland's Royal DSM NV sells a synthetic version called resVida, which is found in supplements, a nonalcoholic fruit-flavored beverage and the new Winetime chocolate-fruit bar.
Resveratrol has found been found in animal studies to prevent or slow progression of illnesses from cancer to cardiovascular disease—and even to extend the life span of some organisms. Since 2008, at least five human studies have been presented at scientific meetings showing human benefits, ranging from improved blood flow to the heart to better control of diabetes.
The newest results are exciting, but some scientists say it is too early for the public to begin taking supplements, which contain as much resveratrol in one pill as dozens or hundreds of bottles of wine, depending on the dose. The proper dose for humans isn't yet known—and more isn't necessarily better.
Researchers at the University of Connecticut School of Medicine in Farmington found that lower doses of resveratrol protected rats' hearts from artificially induced heart attacks while high doses actually made the attacks worse.
While some safety studies have been conducted on humans, it is too early to know if there are long-term side effects of high doses, says S. Jay Olshansky, a professor of epidemiology at the University of Illinois at Chicago. "I cannot emphasize enough: Do not experiment on your own body," he says.
Joseph C. Maroon, a neuroscientist at the University of Pittsburgh Medical Center who has written a book on resveratrol, agrees that more studies are needed but doesn't think it's unreasonable to take a moderate dose of resveratrol. "I don't see any significant downside," he says.
Dr. Maroon says animal data suggest 50 to 1,000 milligrams a day is an effective dose; he takes 300 milligrams daily—which he says contains the amount of resveratrol in some 150 bottles of wine.
No one knows exactly how resveratrol works, but scientists believe it activates a wide range of genes, creating a cascade-like effect on a variety of body functions. Human data include a 100-person placebo-controlled study by Sirtris Pharmaceuticals Inc. that found lowered blood-glucose levels in diabetics who took the GlaxoSmithKline unit's proprietary formulation, SRT501, not yet on the market.
A 19-person study presented earlier this month at a British scientific conference, sponsored by Royal DSM, found that "flow mediated dilation," a measure of cardiovascular health, increased an hour after taking resVida. At an American College of Sports Medicine conference last year, Dr. Maroon and colleagues reported that a three-month study of 51 people found a resveratrol-containing supplement not currently on the market increased endurance on a stationary bicycle compared with a placebo, and also increased verbal memory scores on a standardized test.
And in a report published earlier this month in the journal Optometry, researchers found that five months' therapy with a Longevinex, a supplement sold by Resveratrol Partners LLC of Las Vegas, resulted in significant improvement of vision of an 80-year-old man who was having difficulty with night driving. The visual measures were subjective but researchers also found a significant decrease in lipofuscin, a granular substance that builds up in aging tissues and is linked to vision decline, says researcher Stuart Richer, chief of optometry at the Veterans Affairs Medical Center in North Chicago. Resveratrol Partners provided the supplements taken by the patient, says Dr. Richer, and he has agreed to conduct a company-funded 24-person follow-up study.
One person isn't enough to prove resveratrol can help age-related vision decline, says Dr. Richer, but "we want to do this in a controlled situation with many patients."
