British researchers have discovered one of the key reasons why green vegetables are so beneficial: they are the source of a chemical signal important to a fully functioning immune system. The signal ensures that immune cells in the gut and the skin known as intra-epithelial lymphocytes (IELs) function properly. The researchers fed otherwise healthy mice a vegetable-poor diet for two to three weeks and found that 70 to 80 percent of the protective cells disappeared. The numbers of IELs serving as a first line of defense and in wound repair depend on levels of a cell-surface protein that is regulated by dietary ingredients found primarily in cruciferous vegetables.
"Exogenous Stimuli Maintain Intraepithelial Lymphocytes via Aryl Hydrocarbon Receptor Activation", Cell, October 13, 2011
A multinational team of researchers has found that low levels of dietary protein can cause excess energy intake and could be a factor in higher rates of obesity. Participants in the study – 16 females and 6 males – spent four days on each of three diets. Those fed a 10 percent protein diet consumed 12 percent more energy over four days than they did on a 15 percent protein diet. Seventy percent of the increased energy intake on the lower protein diet came from snacks. The researchers said their findings have considerable implications for bodyweight management at a time when “foods rich in fat and carbohydrate are cheap, palatable and available” to an unprecedented extent.
"Testing Protein Leverage in Lean Humans: A Randomised Controlled Experimental Study", PLoS One, October 13, 2011
U.S. and German researchers have found evidence that vitamin D – which is known to be instrumental in bone development – also seems to protect against cancer and autoimmune diseases and fight infections such as tuberculosis. The team discovered that certain white blood cells that play a central role in immunity release a protein called interferon-g that directs infected immune cells to attack invading tuberculosis bacteria. However, this activation requires sufficient levels of vitamin D to be effective. The next step is to launch clinical trials to learn whether vitamin D supplements can enhance the body's resistance to tuberculosis, which causes 1.8 million deaths a year, the researchers said.
"Vitamin D Is Required for IFN-γ–Mediated Antimicrobial Activity of Human Macrophages", Science Translational Medicine, October 12, 2011
A University of Michigan phase 2 clinical study has found that ginger root supplements reduced markers of colon inflammation and may have potential to prevent colon cancer. Inflammation has been implicated in prior studies as a precursor to colon cancer. For the study, 30 patients were randomly given either two grams of ginger root supplements a day or a placebo for 28 days. The researchers then measured standard colon inflammation markers and found statistically significant reductions in most, and trends toward significant reductions in others. The researchers said another trial would be needed to see how ginger root actually affects the risk of cancer.
"Phase II Study of the Effects of Ginger Root Extract on Eicosanoids in Colon Mucosa in People at Normal Risk for Colorectal Cancer", Cancer Prevention Research, October 11, 2011
A Dutch study has found that consumption of fruits and vegetables with white flesh may prevent the incidence of stroke. For the study, researchers examined the association between consumption of fruits and vegetables in various color groups – green, orange/yellow, red/purple and white – with stroke incidence over ten years among 20,069 adults. The participants were free of cardiovascular disease at the start of the study, but 233 eventually suffered strokes. Green, orange/yellow and red/purple fruits and vegetables weren't related to stroke, researchers found. But the risk of stroke dropped by 52 percent for those who ate a lot of white fruits and vegetables – such as apples, pears and cauliflower. They found that each 25-gram-per-day increase in white fruits and vegetable consumption lowered the risk of stroke by nine percent.
"Colors of Fruit and Vegetables and 10-Year Incidence of Stroke", Stroke, September 16, 2011
Indian researchers who looked at the impact of dietary vitamin A on the activity of an enzyme that controls glucose metabolism have found that the vitamin reduced abdominal fat and overall body weight in obese rats. The animals in the study were fed either a vitamin A-enriched diet or a standard diet. At the end of the experiment, the researchers found that the vitamin A diet “significantly decreased body weight, visceral fat mass and 11b-HSD1 [the enzyme] activity in visceral fat of the obese rats.” The researchers suggested that further research is needed to understand how 11b-HSD1 activity is regulated by nutrients like vitamin A. The results of that research may lead to development of dietary therapies to prevent obesity and insulin resistance.
"Vitamin A decreases pre-receptor amplification of glucocorticoids in obesity: study on the effect of vitamin A on 11beta-hydroxysteroid dehydrogenase type 1 activity in liver and visceral fat of WNIN/Ob obese rats", Nutrition Journal, June 23, 2011
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Pediatric Research, October 01, 2011
EurekAlert, September 27, 2011
British Journal of Nutrition, September 20, 2011
Norwegian University of Science and Technology (NTNU) press release, September 19, 2011
Journal of Physiology, September 01, 2011
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