2011 Science News of the Year: Nutrition

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The value of vitamin D

The simmering debate over vitamin D came to a boil as the scientific organization representing hormone experts embraced daily recommendations for the vitamin that far exceed those put forward in late 2010 by a U.S. Institute of Medicine panel. The Endocrine Society asserted in July that people need two to three times as much vitamin D as the IOM had recommended (SN: 7/16/11, p. 22). The IOM daily levels top out at 600 to 800 international units for most people, the amount found in many multivitamins.

In calling for substantially more D, the endocrinologists cited widespread deficiency in all age groups and pointed out that very few foods naturally contain the vitamin.

A torrent of recent studies have linked vitamin D deficiency — particularly at northern latitudes — with heart disease, cancer, infections, asthma, preterm births, high blood pressure and, among the elderly, difficulty with mental tasks. Two trials now in progress in the United States and New Zealand may clarify the vitamin’s health-giving potential. But results are still several years off. Nathan Seppa

Scant B12  Studies in the elderly link impairments of memory and reasoning with vitamin B12 deficiency. And brain scans show that people lacking B12 are more likely to have shrinkage of brain tissue and vascular damage (SN Online: 9/27/11).

Dietary details  An analysis assigning pounds of weight gain to foods finds that fries, sodas and several other guilty pleasures are among the worst waist expanders (SN: 7/30/11, p. 10).

Yogurt letdown  Eating yogurt doesn’t lead to long-lasting changes in a person’s mix of intestinal microbes (SN: 11/19/11, p. 18).

On the mind  Obesity subtly diminishes memory and other features of thinking and reasoning even among seemingly healthy people, possibly by damaging the wiring that links the brain’s info-processing regions (SN: 4/23/11, p. 8).

Brainy sabotage  Obese people’s brains respond to food as if the body were hungry even when it isn’t, suggesting dieters may be on the losing side of a battle with neural centers that promote eating (SN: 10/22/11, p. 16).

Chocolate diet  Compounds in chocolate can ratchet down digestive enzymes that the body relies on to absorb and use fats and carbohydrates (SN Online: 5/9/11).

Saffron surprise Tests show that saffron can stifle liver cancer in rats (SN: 10/8/11, p. 14).

Blueberry boon Heart-healthy compounds found in blueberries limit the buildup of fat in mouse cells (SN Online: 4/20/11).

Dioxin flare-up  Frying at high temperatures can trigger the development of potentially toxic dioxins and furans in food (SN Online: 5/9/11).

Cough for quality Sensor molecules found in the human throat latch onto a chemical in superior olive oils, providing a scientific basis for the age-old custom of rating superlative oils on a scale of one, two or three coughs (SN Online: 1/18/11).