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AJCN Oct, 2007

Thanks for the many responses to my last nutrition research email. Almost everyone preferred the essay format. I try to state only what is stated in the published peer-reviewed research in AJCN and J. Nutr, but translate it into less technical vocabulary. The links in each statement still go to the actual publication, so you can double check or read further by clicking the blue links.

EVERYONE: More good news for taking your vitamin C twice a day. Vitamin C helps prevent wrinkles! "Conclusions: Higher intakes of vitamin C ... and lower intakes of fats and carbohydrates are associated with better skin-aging appearance. Promoting healthy dietary behaviors may have additional benefit for skin appearance in addition to other health outcomes in the population."

Beware of high fructose corn syrup. It is a major added ingredient especially in drinks like juice and soda, so check the nutritional ingredients label. Fructose is sweeter than sugar but rewards you only with calories, may be the main cause of obesity, and is a potential risk factor for heart disease. "Milk, the main nourishment for infants, has essentially no fructose, and neither do most vegetables and meats, which indicates that human beings had little dietary exposure to fructose before the mass production of sugar...Soft drink consumption, which provides most of this fructose, has increased dramatically in the past 6 decades, rising from a per-person consumption of 90 servings/y (2 servings/wk) in 1942 to that of 600 servings/y (2 servings/d) in 2000 (5)."

Low fat and moderate carbs with fiber seems safest - beware of carbs and high fat diets. Here are four studies showing extremes of either are dangerous. High-fat diets are hazardous, but high carb diets did not have the bad effect. Many have written about the hazard of the Atkins diet, and this study shows how a high fat meal blocks the proper function of your cells, causing a dangerous rise in fat levels. *Another study showed a high carb diet reduced LDL (bad cholesterol), while a low carb diet decreased hypertension. Confusing, but it looks like moderation is sensible unless you have a particular concern. *Consider a few carrots or celery for an appetizer. A serving of 33 g fiber reduced appetite, lowered food intake, and reduced high blood sugar 75 minutes later. *But high glycemic load diets [DEFINITION] are hazardous if you are concerned about breast cancer. This study showed 60-150% higher rate of breast cancer in women based on the glycemic index and glycemic load[DEFINITION] of their meals, especially in those who were overweight. *Avoid the refined carbs!"Conclusion: Persons at risk of age-related macular degeneration (AMD) progression, especially those at high risk of advanced AMD, may benefit from consuming a smaller amount of refined carbohydrates."

Calcium requirement is even lower. Americans once were thought to need 2000mg, then 1200, then 1000, this study shows that 741mg/day is all 95% of people need. "Neither age nor sex affected the estimates..." If you want strong bones, the key is exercise and tea(see below), not calcium pills. *The hazardous side of milk! Although the milk industry has been very effective at convincing the American public that milk is a great source of calcium, "These data suggest that a high intake of dairy fat is associated with a greater risk of ischemic heart disease." Tums are an easy way to get a readily absorbed dose of calcium- 200mg twice a day for younger people, 400mg twice a day for mature people. This study is about milk fat, so skim milk does not have this hazard.

Soybeans are great for reducing the risk for heart disease. They are rich in isoflavones.

CHILDREN - Here's the design for a multivitamin/mineral/fish oil supplement for children's brains! "Conclusion: In well-nourished school-aged children, fortification with multiple micronutrients can result in improvements in verbal learning and memory." Make sure children get a micronutrient mix (iron, zinc, folate, and vitamins A, B-6, B-12, and C), with fish oil (88 mg DHA and 22mg EPA). Note this study started with well-nourished children, so this supplementation is above and beyond healthy eating. A good multivitamin and occasional fish oil tablets will accomplish this. *Get children (and adults) a good breakfast, even with sugar. This study shows that breakfast has a lasting effect on appetite throughout the day. In particular, a breakfast with a high glycemic index provides a satiating effect all day, while sweets later in the day do not control hunger very long.

BABIES - Take that prenatal vitamin. Successful pregnancies were significantly and positively associated with vitamin E and vitamin A levels in the umblical cord. These two vitamins may just be biomarkers for why birth weight and head circumference were healthy.

MATURE PEOPLE - Zinc is critical to health. Just 50% of the Daily Value in a supplement makes a life-saving difference. "Conclusion: Normal serum zinc concentrations in nursing home elderly are associated with a decreased incidence and duration of pneumonia, a decreased number of new antibiotic prescriptions, and a decrease in the days of antibiotic use. Zinc supplementation to maintain normal serum zinc concentrations in the elderly may help reduce the incidence of pneumonia and associated morbidity."*And drink tea for stronger bones! "Conclusion: Tea drinking is associated with preservation of hip structure in elderly women. This finding provides further evidence of the beneficial effects of tea consumption on the skeleton."


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