SCIENTIFIC UPDATE
Adequate Calcium Important for Vegan Bone Health
How much calcium do vegans need? A recently published study from the U.K. helps to provide the answer. Researchers from Oxford University studied more than 34,000 adults. Subjects included meat-eaters, fish-eaters, lacto-ovo vegetarians, and vegans. Subjects were asked about their diet and exercise habits and if they had had a fractured bone in the past six years. Average calcium intakes of vegans were lower than the other groups, and more than three-quarters of the vegans had a calcium intake below the U.K. recommendation of 700 milligrams of calcium daily. Approximately 1,800 subjects reported one or more fractures, with the wrist, arm, and ankle being the most common fracture sites. Vegans had a 30 percent higher fracture rate than the other groups. When only those vegans who consumed at least 525 milligrams of calcium a day were examined, the difference in fracture rates among the groups disappeared. In other words, meat-eaters, fish-eaters, lacto-ovo vegetarians, and vegans getting at least 525 milligrams of calcium all had a similar risk of fracturing a bone, while vegans with lower calcium intakes had a higher risk of fracture. Protein intake did not appear to affect fracture risk in this study. These results suggest that it is important for vegans to get adequate calcium from sources like kale, bok choy, collards, mustard greens, calcium-set tofu, calcium-fortified soymilk or juice, or a calcium supplement.
Appleby P, Roddam A, Allen N, Key T. Comparative fracture risk in vegetarians and nonvegetarians in EPIC-Oxford. Eur J Clin Nutr 2007 Feb 7. Advance online publication.
How Many Fruits and Vegetables Do You Eat?
The U.S. Dietary Guidelines recommend eating at least three to five servings of fruit and four to eight servings of vegetables daily. However, a 2005 survey of close to 350,000 adults in the U.S. found that, on average, people in the United States eat 1.6 servings of fruit and 3.2 servings of vegetables, well below recommendations.1 When we look at teens, the numbers are even more troubling. On average, high school-aged boys and girls ate less than two servings of vegetables and less than two servings of fruit daily.2 Students ate fewer fruits and vegetables as they moved from junior to senior high school and after high school graduation. This is of special concern because the teen years are times when lifelong dietary habits are being developed and because kids who eat more fruits and vegetables have stronger bones. We know vegetarians are above average in many ways. We hope that one of these is the number of servings of fruits and vegetables eaten.
1 Centers for Disease Control and Prevention. 2007. Fruit and vegetable consumption among adults — United States, 2005. MMWR Morb Mortal Wkly Rep 56:213-17.
2 Larson NI, Neumark-Sztainer D, Hannan PJ, Story M. 2007. Trends in adolescent fruit and vegetable consumption, 1999-2004. Project EAT. Am J Prev Med 32:147-50.
People Who Eat a Plant-Based Diet Live Longer
A large study that is being conducted in 10 European countries aims to look at dietary patterns and health in older people. More than 500,000 people, age 60 and older, are included in this investigation. In one part of this project, approximately 74,000 participants were divided into three groups based on their dietary pattern. One group, which had the highest 'plant-based' score, had high intakes of vegetables, fruit, dried beans, grains, and vegetable oils. People in this group tended to be from France, Greece, Italy, and Spain. Another group, with the lowest 'plant-based' score had high intakes of meat, dairy products, margarine, and potatoes and low intakes of fruits, vegetables, and grains. Many people from Sweden and Denmark were in this group. A third group was intermediate with medium amounts of fruits, vegetables, meat, and dairy products and an intermediate 'plant-based' score. The group with the highest 'plant-based' score had a markedly lower mortality (risk of dying from any cause) than either of the other two groups. These results are similar to those seen in California Seventh-day Adventists and in elderly Japanese. Eating a more plant-based diet appears to lead to a longer life.
Barnia C, Trichopoulos D, Ferrari P, et al. 2007. Dietary patterns and survival of older Europeans: the EPIC-Elderly Study (European Prospective Investigation into Cancer and Nutrition). Public Health Nutr 10:590-98.
Harvesting Vegetables and Grains May Result in Fewer Animal Deaths Than Many Previously Thought
Both academic research and media reports have popularized the idea that harvesting crops like wheat, soybeans, and corn kills large numbers of mice, voles, and other field animals. Because these crops are the basis of many vegetarians' diets, some have used these findings to question the ethical basis of vegetarian and vegan diets. A new report examining the issue, however, concludes there is little evidence to support this view. Andy Lamey, a doctoral student at the University of Western Australia, has re-examined an earlier analysis by Steven Davis, an animal scientist at Oregon State University, which concluded that a relatively small number of animals were killed to produce grass-fed beef. Lamey raises key questions about the number of animal deaths caused by farm machinery compared to those due to animal predators and about the statistics that Davis used. In addition, Lamey points out that animal agriculture poses many more risks to humans (such as slaughterhouse accidents) than does vegetable production. Based on his analysis, Lamey concludes that vegetarians and vegans should not change their diets due to a concern about field animal deaths.
Lamey A. 2007. Food fight! Davis versus Regan on the ethics of eating beef. J Soc Philosph 38:331-48.
Diet and Skin Cancer
Skin cancers, including melanoma, basal cell cancer, and squamous cell cancer, are the most common of all cancers. New research suggests that diet may play a role in the development of at least one kind of skin cancer, squamous cell cancer. Each year, between 200,000 and 300,000 people in the United States are diagnosed with this cancer, and the incidence rate is rising. Researchers in Australia studied more than 1,000 adults over an 11-year period to see which factors were associated with skin cancer. Even when factors like sun exposure and skin color were taken into account, people who ate a lot of red or processed meat and high-fat dairy products had a greater risk of developing squamous cell cancer. This was especially true for people who had already had skin cancer. Those eating more fruits, vegetables, and whole grains and having a lower fat diet had a 54 percent lower risk of developing squamous cell cancer. Of course, the most important way to reduce risk of skin cancer is to avoid excess sun exposure and to use sunscreen. Eating generous amounts of fruits, vegetables, and whole grains can also reduce your risk.
Ibiebele TI, van der Pols JC, Hughes MC, et al. 2007. Dietary pattern in association with squamous cell carcinoma of the skin: a prospective study. Am J Clin Nutr 85:1401-1408.
More Reasons to Eat Organic
Most people would agree that organically produced foods are better for the environment because synthetic fertilizers and pesticides are not used. Several recent studies also suggest that organically grown foods have a higher level of some key nutrients than do conventionally grown foods. A study1 of organically grown kiwis found that they had higher levels of vitamin C, potassium, calcium, magnesium, and phosphorus. Organically grown kiwis also had a darker green color and a thicker skin and tended to ripen faster than conventionally grown kiwis.
Organically grown wheat was shown to be comparable to conventionally grown wheat in terms of the quality of baked products made from each kind of wheat and the nutritional value.2 Despite not being treated with fungicides, organically grown wheat was no more likely to be contaminated with fungus than conventionally grown wheat.
1 Amodio ML, Colelli G, Hasey JK, et al. 2007. A comparative study of composition and postharvest performance of organically and conventionally grown kiwifruits. J Sci Food Agric 87:1228-36.
2 Mader P, Hahn D, Dubois D, et al. 2007. Wheat quality in organic and conventional farming: results of a 21 year field experiment. J Sci Food Agric (in press).
