Fish oil does not improve cognitive function, according to new research. Researchers in England found that fish oil did not benefit the cognitive function of elderly adults after two years of daily supplementation. In a double-blind control trial, 867 people with a mean age of 75 years were assigned to either a fish supplement (200 mg EPA plus 500 mg DHA) or placebo (olive oil) group. Participants were given various tests for cognition including reaction time, spatial memory, and processing speed measurements. No significant differences were seen between groups.

Dangour AD, Allen E, Elbourne D, et al. Effect of 2-y n23 long-chain polyunsaturated fatty acid supplementation on cognitive function in older people: a randomized, double-blind, controlled trial1–3. Am J Clin Nutr. Published ahead of print April 21, 2010. doi: 10.3945/ajcn.2009. 29121.

McDougall says that Vitamin D pills can be of little benefit, and some harm: “Low vitamin D levels found in the blood are a clear indication that there is a worldwide problem of sunlight deficiency. Rather than correct the problem and encourage people to expose themselves to more of this natural element, the solution has become another drug — a supplement pill sold as vitamin D.”

McDougall also reviews his five favorite articles from recent medical journals.

And, of course, recipes including Soba Miso soup, wok-stirred noodles, baked tofu, asparagus and pea salad, Spanish garbanzos and spinach, overnight multi-grain cereal, low-energy-dense soup, and sunny citrus salad dressing.

Researchers in China estimated that 9.7 percent (92.4 million) of Chinese adults had diabetes, and an additional 15.5 percent (148.2 million) had prediabetes during 2007 and 2008. The China National Diabetes and Metabolic Disorders Study looked at 46,239 adults in a wide range of provinces and municipalities. Previous surveys showed diabetes to affect approximately 3 percent of the population in 1994, and 5 percent in 2000 and 2001.

Urban populations had the highest risk of diabetes; urbanization in developing countries is associated with Westernized diets, physical inactivity, and obesity. Diabetes is a major risk factor for cardiovascular disease, the leading cause of death in China.

Yang W, Lu J, Weng J, et al. Prevalence of diabetes among men and women in China. N Engl J Med. 2010;362:1090-1101.

An increase in childhood obesity reflects increased intake of oils, meat, cheese, and frozen desserts, according to a new PCRM study that will be published next month in the American Journal of Clinical Nutrition. Neal Barnard, M.D., looked at food availability data maintained by the U.S. Department of Agriculture from 1909 to 2007. Oil intake increased from 35 pounds to more than 86 pounds per person per year. Meat intake rose from 123 pounds to more than 200 pounds per person per year (with a greater than six fold increase in chicken and turkey intake alone). In 2007, Americans also ate nine times more cheese and 16 times more frozen desserts than they did in 1909. Since 1970 (no prior data available), sweetener consumption doubled, mostly from carbonated beverages. Other long-term trends include decreased grain consumption, decreased fluid milk consumption, and increased fruit (mostly juices) and vegetable intake.

Barnard ND. Trends in food availability, 1909-2007. Am J Clin Nutr. 2010;91(suppl):1S-7S.

Taxing unhealthful foods may be an effective way to control weight and prevent common chronic diseases, according to a new study. As part of the Coronary Artery Risk Development in Young Adults (CARDIA) Study, researchers looked at 20 years of food intake, food costs, and health outcomes for 5,115 participants. They found that as the price of foods—specifically soda and pizza—increased, intake decreased, leading to fewer calories consumed, lower body weights, and improved insulin function.

Duffey KJ, Gordon-Larsen P, Shikany JM, Guilkey D, Jacobs Jr. DR, Popkin BM. Food price and diet and health outcomes: 20 years of the CARDIA Study. Arch Intern Med. 2010;170:420-426.

Women with the highest fruit and vegetable intakes have better ovarian cancer survival rates than those who generally neglect these foods, according to a new study in the Journal of the American Dietetic Association. Researchers examined food patterns prior to ovarian cancer diagnosis in 341 Illinois women. They found that yellow and cruciferous vegetables, in particular, contributed to longer survival, whereas consumption of dairy products and red and processed meats shortened lifespan. The authors concluded that low-fat, plant based diets are not only beneficial for cancer prevention—they may also play a role in increasing survival time after diagnosis. Ovarian cancer is the fifth leading cause of cancer-related death among women in the United States.

Dolecek TA, McCarthy BJ, Joslin CE, et al. Prediagnosis food patterns are associated with length of survival from epithelial ovarian cancer. J Am Diet Assoc. 2010;110:369-382.

Consumption of soy, fruits, and vegetables helps reduce the risk of developing breast cancer, according to a new study published in the American Journal of Clinical Nutrition. Postmenopausal women who consumed plenty of soy, fruits, and vegetables had a 30 percent lower risk of developing breast cancer, compared with those who consumed relatively little of these foods. The research was based on 34,028 women in the Singapore Chinese Health Study. The longer the women had consumed these healthful foods, the less chance they had of developing breast cancer.

Butler LM, Wu AH, Wang R, Koh WP, Yuan JM, Yu MC. A vegetable-fruit-soy dietary pattern protects against breast cancer among postmenopausal Singapore Chinese women. Am J Clin Nutr. Published ahead of print February 24, 2010. doi: 10.3945/ajcn.2009.28572.

In his January newsletter, McDougall reveals the top five poisons only found in animal products.

He also promotes a new inter-dental brushing tool

As well as recipes for lentil curry soup, minestrone, quick black beans, beans and greens, and spicy garbanzos.

In his February newsletter, McDougall speaks out against early cancer detection, where he says the chance of harm outweighs any benefit.

He then invites President Bill Clinton to attend the McDougall Program: “The only solution is to allow the body to heal your steadily-progressing disease by making serious dietary changes.”

The recipes include some chef-inspired fare from their Advanced Study weekend, such as BBK Soup, Spicy Sweet Squash Stew, Red Posole, Mexican Green Quinoa, and Tangy Lime Cole Slaw.

Animal protein is associated with decreased bone health, according to a study in this month’s British Journal of Nutrition. In Beijing, China, 757 girls with an average age of 10 years were randomly assigned to a group consuming cow’s milk fortified with calcium, one consuming cow’s milk fortified with calcium and vitamin D, or a third group that served as controls and made no changes. Bone mass was measured at the beginning of the study and at 12, 24, 48, and 60 months. While calcium intake was positively associated with bone health, animal protein, especially from meat and eggs, was negatively associated with bone mineral density and content.

Zhang Q, Ma G, Greenfield H, et al. The association between dietary protein intake and bone mass accretion in pubertal girls with low calcium intakes. Br J Nutr. 2010;103:714-723.