The RDA method

In a study at the Division of Human Nutrition, Wageningen University, in the Netherlands, researchers randomly assigned 818 participants 800 mg daily oral folic acid or placebo for 3 years. The effect on cognitive performance was measured as the difference between the two groups in the 3-year change in performance for memory, sensorimotor speed, complex speed, information processing speed, and word fluency.

The 3-year changes in memory (difference in Z scores 0.132, 95% CI 0.032 to 0.233), information processing speed (0.087, 0.016 to 0.158) and sensorimotor speed (0.064, -0.001 to 0.129) were significantly better in the folic acid group than in the placebo group.

The World Cancer Research Fund published a long, detailed report, collating much research. It is worth reading through the several hundred pages.

http://www.dietandcancerreport.org/?p=ER

Chapter 4 is particularly relevant for those interested in nutrition - not just for the interaction between foods and cancer, but for other health effects. See also Chapter 8, on exercise.

Chapter 4 Foods and drinks 66
4.1 Cereals (grains), roots, tubers and plantains 67
4.2 Vegetables, fruits, pulses (legumes), nuts,
seeds, herbs, spices 75
4.3 Meat, poultry, fish and eggs 116
4.4 Milk, dairy products 129
4.5 Fats and oils 135
4.6 Sugars and salt 141
4.7 Water, fruit juices, soft drinks and hot drinks 148
4.8 Alcoholic drinks 157
4.9 Food production, processing, preservation

A study from Australia measured the relationship of tea consumption to hip bone density in elderly women. The tea drinkers had slightly better bone density, measured over 5 years, than the non-tea drinkers. The abstract does not mention whether the tea was drunk plain, or with milk. Anyone from Australia care to comment on what would be usual ? In the UK it would be reasonable to assume the tea would be black, and drunk with milk. In the US the default is no milk.

"Tea drinking is associated with benefits on bone density in older women" - abstract from a research paper by the University of Western Australia, and others, in the American Journal of Clinical Nutrition. Access to the full article requires a subscription.

Higher intakes of vitamin C and linoleic acid and lower intakes of fats and carbohydrates are associated with better skin-aging appearance.

"Dietary nutrient intakes and skin-aging appearance" - abstract from a research paper published by Unilever (UK) in the American Journal of Clinical Nutrition. Access to the full article requires a subscription.

abstract Vol. 86, No. 4, 1225-1231, October 2007

There seems to be an upswing in interest in in reporting about the effects of bacteria in the digestive system ..probably because probiotic drinking yogurts are currently the fastest growing dairy product in Europe. Inulin is a soluble fiber, found in chicory root, yams, artichokes, onion, garlic, and agave. Added to yogurt, it increases the absorption of calcium, as well as making non-fat yogurts taste smoother.

The Wikipedia entry on Inulin suggests that it is useful for managing blood sugar levels. So yogurt, or other foods containing Inulin, might help to smooth the blood sugar spikes which affect mood and energy levels.

"Symptoms of IBS seem to improve by controlling production of GI hormones, principally insulin, by The Zone Diet.
IBS may be hormonally mediated in response to excess dietary sugar & refined carbohydrate."

Anthony J Dowell, BC Surgical Society, 2002. http://www.bcss.ca/zonediet.ppt

Eat more vegetables, reduce your likelihood of cancer (why only head and neck cancer ?)
Eat less red meat, especially if you are female.

Do articles like these make any difference to what you choose to eat, or is it too hard to sort out valid research from research work funded by sellers of certain foods or supplements ?

"A large study of 500,000 American retirees has found that just one extra serving of fruit or vegetables a day may reduce the risk of developing head and neck cancer.
Numerous studies have demonstrated that diet plays a role in cancer. Cancer experts now believe that up to two-thirds of all cancers come from lifestyle factors such as smoking, diet and lack of exercise."

Courtesy of a friend who is both a medical doctor, and an enthusiastic wine consumer ..

More reasons to get enough calcium and vitamin D - colorectal cancer

"High total calcium intake (from food and supplements) lowered the risk of colorectal cancer in both men and women. Comparing the highest calcium intakes with the lowest, the risk of developing colorectal cancer was reduced by 30 percent for men and by 36 percent for women.

"Total vitamin D intake was inversely associated with colorectal cancer risk in men but not in women," Park and colleagues report.

A high intake of dairy products also reduced the risk of colorectal cancer risk, especially for people who didn't take supplemental calcium; the risk reduction was 23 percent for men and 34 percent for women."

American Journal of Epidemiology, March 2007.

After 12 weeks on the low-carb plan, study participants had lost an average of 4.9 kilograms (10.8 pounds), compared to 2.5 kg (5.5 pounds) for their peers on the low-fat diet."

"However, after the weight-maintenance phase of the study, which lasted another 24 weeks, differences between the two groups in weight loss and fat mass remained, but were no longer statistically significant."