Thursday, August 30, 2012
For many baby boomers, former president Bill Clinton among them, vegetarian diets — including vegan ones, which eschew all animal products — have become a way of life. Much of the reason for that, doctors say, is that this demographic group is heading into prime time for health issues and sees vegetarianism as a way to protect their bodies. Yet for boomers these diets can carry some risks that don't concern those in their 30s or 40s. As we age, our nutritional needs change and are harder to meet.
About 2.5 million Americans over the age of 55 are vegetarian according to a 2012 Harris poll conducted for the Vegetarian Resource Group, and doctors and researchers say interest in such diets is growing. The prominence of some aging vegetarians stokes this trend: In addition to Clinton (age 65), there is Paul McCartney (70), retired tennis player Martina Navratilova (55) and actor Ian McKellen (73). Less famous but nevertheless impressive vegetarians include Fauja Singh, an India-born Briton who at 101 years old runs marathons.
It's clear from research that forgoing meat can improve health. “Vegetarianism can be used as a way to combat many conditions that plague boomers: heart disease, Type 2 diabetes, obesity. We now know, for example, that such a diet can lower your blood pressure,” says Boston University registered dietitian Joan Salge Blake, citing numerous recent studies.
In an article published in 2005, Susan Berkow, a certified nutrition specialist, and physician Neal Barnard analyzed 11 observational studies and found that vegetarians tend to have lower blood pressure than meat-eaters. The reasons behind this are not well understood.
According to the authors (both of whom are affiliated with the Physicians Committee for Responsible Medicine, which promotes a vegetarian diet), probably one of the most important is the generally lower body weight of vegetarians due to the abundance of fiber in their diets, which causes them to feel full faster and helps with insulin control.
Since the risk of death from a stroke in middle age rises significantly as blood pressure rises, it is no surprise that vegetarians tend to face fewer cardiovascular issues than the rest of us.
In an article published in April in the Archives of Internal Medicine, Harvard researchers found that the more red meat you usually consume, the more likely you are to succumb to heart disease. Adding three ounces of meat to your daily diet (above what you normally eat) elevates the risk of death from cardiovascular disease by 16 percent.
For processed meat (think sausages and bacon), the numbers are even more striking: Increasing consumption by one serving a day — that would be just one more hot dog — elevates the long-term risk of death from cardiovascular disease by 21 percent.
Beyond damaging your heart, researchers tend to agree, eating red meat increases the risk of colorectal and other cancers.
Similarly, a 2004 investigation by researchers from the Harvard Medical School found that middle-aged and older women who ate red meat more than five times a week had a 29 percent higher risk of developing Type 2 diabetes than those who indulged in it less than once per week. The Centers for Disease Control and Prevention calculated that in 2010 almost 27 percent of Americans over the age of 65 had diabetes.
Researchers studying 41,000 Seventh-day Adventists found that eating meat increased their risk of diabetes. The scientists pointed to hamburgers, bacon and hot dogs as the worst offenders.
A review of 27 studies published in 2009 in the American Journal of Cardiology, meanwhile, showed that forgoing meat of all kinds can decrease blood cholesterol levels by at least 10 to 15 percent.
It's not just that these diets are low in saturated fats, authors say: What also helps are plant sterols and soluble fiber, which increase cholesterol removal.
Before you rush to give the steak you were planning to eat tonight to the first dog you see, consider that being a vegetarian, and especially following a vegan diet, can pose challenges specific to boomers.
In particular, such regimes, if poorly planned, may be relatively low in protein, calcium, Vitamin B12 and zinc. “These nutrients are especially important in aging to support wound-healing and to keep a healthy immune system,” says Sylvia Escott-Stump, president of the Academy of Nutrition and Dietetics (formerly the American Dietetic Association).
As we get older, many of our mineral and vitamin requirements increase, and we need fewer calories to maintain our weight. For this reason, it might be harder to go vegetarian at age 50 than it was earlier.
“You have to make sure the calories you eat are very nutrient-rich per bite; otherwise your health might suffer more, and faster, than that of a younger person,” advises Boston University's Salge Blake.
“For example, an eight-ounce glass of skim milk is not only lower in calories than a soft drink but also contains calcium, Vitamin D and potassium, which are nutrients many older adults are falling short of in their diets.” This, though, can be true for meat-eaters as well as vegetarians.
One of the most common deficiencies in people over the age of 50 is that of Vitamin B12, the main sources of which are meat, fish, milk and eggs. “At this stage of life, 10 to 30 percent of individuals malabsorb this vitamin because they have less acidic juices in the stomach,” explains Salge Blake.
Research suggests that if your diet is poor in this nutrient, you may be at increased risk of anemia, hearing loss, dementia or Alzheimer's disease.
A study published in 2000 in the Annals of Nutrition and Metabolism showed that about 50 percent of vegans have below-normal levels of B12. Some vegans suggest that it is possible to get B12 from seaweed or spirulina, but that type of algae contains only ineffective analogs, according to studies of the vitamin, which may even block its metabolism.
The only solution is supplementation (which is recommended by many nutritionists to all people older than 50).
Also, anemia is much more common after age 50. Boomers should therefore be careful to ensure they are getting enough iron, which can be hard with a plant-only diet.
“Animal foods provide 'heme' sources of iron [a form of dietary iron from animals], which are more readily digested than 'non-heme' plant sources” says Escott-Stump.
“People eating only plant foods may need to increase their total intake of iron-rich products along with a source of Vitamin C to use the iron better.”
You can find iron in dark green leafy vegetables, prune juice, dried beans and bulgur.
Interestingly, studies indicate that iron deficiency appears to be no more common in vegetarians than in meat-eaters, possibly because vegetarians know they are at risk and eat to deal with that. “In our lab we have noticed that when people become vegetarian, the amount of iron in their diet actually goes up.
By eating legumes and green leafy vegetables, they tend to consume larger amounts of the nutrient, making up for the worse absorption of 'non-heme' iron,” says Barnard.
Another source of concern for some boomers who go vegetarian is calcium. “Post-menopausal women are prone to osteoporosis, which has mistakenly prompted some doctors to recommend dairy products,” says Barnard.
“However, the Nurses' Health Study conducted at Harvard University showed that women who drank milk had as many fractures as those who avoided it.”
Unless vegans consume a lot of fortified tofu and soy milk, as well as green leafy vegetables and beans, their intake of calcium may be inadequate. A review of nine studies published in 2009 in the American Journal of Clinical Nutrition suggests that the risk of fracture in vegans is about 10 percent higher than in omnivores.
The good news is that lacto-ovo vegetarians (those who eat dairy products and eggs) are not any more likely to break their hips or wrists than people who eat meat.
If you are a boomer considering cutting your meat intake, you should make sure you will be getting enough zinc, which is important for proper functioning of the immune system.
Without it, bodies are less resistant to pathogens, and wounds take longer to heal. Yet older people commonly don't meet their needs for this nutrient.
According to the authors of a 2010 article in Nutrition Reviews, insufficient zinc in diet as people age can lead to more frequent bouts of pneumonia, and more complications.
Pneumonia is one of the five leading causes of death for older Americans. But if your diet is well planned that should not be a problem.
So how old is too old to go vegetarian? “A hundred twenty-three,” Barnard laughs. “And I'm only saying this because the longest-lived person was 122.”