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Obesity may interfere with Vitamin D absorption

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The more obese a person is, the poorer his or her vitamin D status, a new study by a team of Norwegian researchers suggests. The study found an inverse relationship between excess pounds and an insufficient amount of vitamin D, which is critical to cell health, calcium absorption and proper immune function. Vitamin D deficiency can raise the risk for bone deterioration and certain types of cancer. The researchers also suggest that overweight and obese people may have problems processing the vitamin properly.

The team noted that after the so-called “sunshine vitamin” is initially absorbed (through either sun exposure or the consumption of such foods as oily fish and fortified milk), the body must then convert it into a usable form, called 1,25-dihydroxyvitamin D. This conversion process, however, seems to be short-circuited among obese people, complicating efforts to gauge their true vitamin D health.

The findings are published in the January issue of the Journal of Nutrition.

To investigate the impact of obesity on vitamin D absorption, the team spent six years tracking 1,464 women and 315 men, with an average age of 49. Based on the participants' body mass index (BMI), an indicator of body fatness calculated from a persons weight and height, the average participant was deemed to be obese. About 11 percent were categorized as “morbidly obese.”

From the outset, overall vitamin D levels were found to be below the healthy range, the authors noted. By the end of the study, overall levels of vitamin D were found to have dropped off “significantly” while BMI readings rose by 5 percent. The research team concluded that having a higher-than-normal weight, body fat and BMI was linked to a poorer vitamin D profile. For example, people with the lowest BMI readings had 14 percent higher vitamin D levels than those with the highest BMI readings. Because vitamin D levels did not correlate properly with 1,25-dihydroxyvitamin D levels (and in fact appeared to have an abnormal inverse relationship), the authors suggested that future efforts to explore vitamin D status among obese people should test for both measures of vitamin D health.

They also suggested that people who are overweight and obese might benefit from vitamin D supplementation and more exposure to sunlight.

SOURCE: Journal of Nutrition, news release, Dec. 14, 2010

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Veggies and exercise improve vision in women

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It's the same advice that mothers everywhere have been giving for years, but now there's science to back it up: Eating veggies is good for the eyes. A new study from the University of Wisconsin confirmed that women who have a healthy diet, exercised regularly and didn't smoke were less likely to suffer macular degeneration as they got older. Macular degeneration is the leading cause of vision problems in older people in the United States, researchers said.

The study of 1,313 women from Oregon, Iowa and Wisconsin is the first to look at several lifestyle factors that influenced age-related macular degeneration (AMD), according to a release from the university. These findings show a healthy lifestyle can improve the chances of good eyesight for those who inherit the condition, according to Dr. Julie Mares of the UW School of Medicine and Public Health.

According to the study, 18 percent of women deemed to have unhealthy lifestyles developed early AMD while just 6 percent of women in the healthy-lifestyle group developed the condition. Researchers found that the association of healthy eyes and healthy overall diets was stronger than what they observed for any single nutrient. Women whose diet score was the in top 20 percent had a 50 percent lower prevalence of early stages of macular degeneration than woman with the lowest percent for healthy diet scores. Higher scores were given to those with more leafy green and orange vegetables, fruits, dairy, grains and legumes, according to the release.

Mares said this was the first study where researchers found higher levels of physical activity lowered the likelihood of early macular degeneration. However, this study didn't show obesity was related to AMD, but obese women were more likely to have more macular degeneration. That trend was explained by a poor diet and low physical activity, according to the university. The study also confirmed other studies that smoking played a role in eye disease.

The university said the study is being published online in the Archives of Ophthalmology, a journal of the American Medical Association. The research was funded by the National Institutes of Health, National Eye Institute. It was also supported by the Research to Prevent Blindness and the Retina Research Foundation.

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Chia seeds – packed with nutrition

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According to a 2007 University of Toronto study published in the journal Diabetes Care, a quarter-cup of chia seeds supplies as much omega-3 fatty acid as a salmon fillet, 25 percent more dietary fiber than flaxseed, 30 percent more antioxidants than blueberries and as much calcium as three cups of milk.

The study, so far the only peer- reviewed one concerning the health claims of chia seeds, showed that diabetes patients reduced cardiovascular risks by ingesting chia seeds along with standard diabetes therapy.

Dr. Sheri Zidenberg-Cherr of the UC Davis nutrition department says chia seeds have a “nice nutritional profile” but hastens to add they are not the dietary cure-all some are trumpeting. “The redeeming qualities of it is omega-3s, specifically the lenlinic (acid) that's in there,” Zidenberg-Cherr says. “Because of that tie-in with heart disease and diabetes, I see potential for it as something that could be added to someone's diet if they're already following a healthy eating plan with the proper recommendations.”

At the very least, she adds, chia seeds can't hurt.

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Wholegrains help lower blood pressure

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Starting the morning with a bowl of porridge and eating a whole-grain sandwich at lunchtime can help cut the risk of high blood pressure, according to new research. A study carried out by scientists from Aberdeen University which involved more than 200 volunteers revealed that eating three portions of whole-grain foods every day lowers the risk of high blood pressure, a major risk factor for heart disease and stroke. A good deal of research has suggested that a whole-grain diet is good for your health, but this study is one of the first to test the theory in a well-designed clinical trial.

Volunteers in the study ate three servings a day of whole-grain foods, which were either wheat, or a mixture of both wheat and oats. The whole-grain diets were compared with one that contained the same amounts of refined cereals and white bread. The study used foods widely available in supermarkets to make the diet easy to follow, without having to make any changes to their usual lifestyle. Apart from the whole-grain and the equivalent refined cereal foods, the volunteers were encouraged to continue with their normal food choices.

Dr Frank Thies, senior lecturer at The Rowett Institute of Nutrition and Health, who led the study, said: “We observed a decrease in systolic blood pressure of 5-6 mm Hg in the volunteers who ate the whole-grain foods, and this effect is similar to that you might expect to get from using blood pressure-lowering drugs. “This drop in systolic blood pressure could potentially decrease the incidence of heart attack and stroke disease by at least 15 and 25 per cent respectively. The scientists also added that wholegrain wheat and oat-based recipes should be on everyone's festive menu this Christmas.

The findings are published in the American Journal of Clinical Nutrition.

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Rice may reduce health risks

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The researchers also looked at the overall health profiles of rice eaters, and learned that the 19- to 50-year-olds who ate rice were less likely to be overweight or obese, had a 34% reduced risk for high blood pressure, 27% reduced likelihood of having abdominal obesity and increased waist circumference and 21% reduced risk of metabolic syndrome. No associations could be drawn for children ages two to 13; however, in children ages 14-18, body weight, waist circumference, triglycerides and diastolic blood pressure were lower (P G .05) among those who ate rice.

“This study shows that eating rice can improve overall diet and reduce risk for the major conditions that afflict more than half of all Americans — heart disease and Type II diabetes,” states Upton. “Rice is a practical solution to help consumers meet dietary guidance to eat more plant-based foods.”

U.S. national nutrition surveillance records show that rice eaters have healthier diets and less risk for chronic diseases compared to non-rice eaters. The researchers reported that rice eaters are:

  • 1/3 less likely to have high blood pressure;
  • 1/4 less likely to have a high waist circumference (often linked to obesity and diabetes risk);
  • 1/5 less likely to have metabolic syndrome.

Research shows U.S. rice consumption has increased steadily over the past 20 years, with current per capita consumption at 26 pounds per person. Surveys show that rice is most frequently served as a side dish or one pot meal.

The research was supported by a grant from the USA Rice Federation.

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New Evidence for Eye-Protective Effects of Omega-3-Rich Fish, Shellfish

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Researchers at Wilmer Eye Institute, Johns Hopkins School of Medicine, wanted to know how the risk of age-related macular degeneration (AMD) would be affected in a population of older people who regularly ate fish and seafood, since some varieties are good sources of omega-3 fatty acids. A diet rich in omega-3s probably protects against advanced AMD, the leading cause of blindness in whites in the United States, according to the Age-Related Eye Disease Study (AREDS) and other recent studies. High concentrations of omega-3s have been found in the eye's retina, and evidence is mounting that the nutrient may be essential to eye health. The new research, led by Sheila K. West, PhD, was part of the Salisbury Eye Evaluation (SEE) study.

Food intake information with details on fish and shellfish consumed was collected over one year using a validated questionnaire for 2,391 participants aged 65 to 84 years who lived along Maryland's Eastern Shore. After dietary assessment was complete, participants were evaluated for AMD. Those with no AMD were classified as controls (1,942 persons), 227 had early AMD, 153 had intermediate-stage disease, and 68 had advanced AMD. In the advanced AMD group, the macular area of the retina exhibited either neovascularization (abnormal blood vessel growth and bleeding) or a condition called geographic atrophy. Both conditions can result in blindness or severe vision loss.

“Our study corroborates earlier findings that eating omega-3-rich fish and shellfish may protect against advanced AMD.” Dr. West said. “While participants in all groups, including controls, averaged at least one serving of fish or shellfish per week, those who had advanced AMD were significantly less likely to consume high omega-3 fish and seafood,” she said.

The study also looked at whether dietary zinc from crab and oyster consumption impacted advanced AMD risk, but no significant relationship was found. Zinc is also considered protective against AMD and is included in an AMD-vitamin/nutrient supplement developed from the AREDS study. Dr. West speculated that her study found no effect because the levels of zinc obtained from seafood/fish were low compared to supplement levels.

The research is published in the December issue of Ophthalmology, the journal of the American Academy of Ophthalmology.

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Can Omega-3 foods prevent eye disease in seniors?

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Eating a diet rich in omega-3 fatty acids appears to protect seniors against the onset of a serious eye disease known as age-related macular degeneration (AMD), a new analysis indicates.”Our study corroborates earlier findings that eating omega-3-rich fish and shellfish may protect against advanced AMD,” study lead author Sheila K. West, of the Wilmer Eye Institute at Johns Hopkins School of Medicine in Baltimore, said in a news release from the American Academy of Ophthalmology.

“While participants in all groups, including controls, averaged at least one serving of fish or shellfish per week, those who had advanced AMD were significantly less likely to consume high omega-3 fish and seafood,” she added.

The observations are published in the December issue of Ophthalmology.

West and her colleagues based their findings on a fresh analysis of a one-year dietary survey conducted in the early 1990s. The poll involved nearly 2,400 seniors between the ages of 65 and 84 living in Maryland's Eastern Shore region, where fish and shellfish are eaten routinely. After their food intake was assessed, participants underwent eye exams. About 450 had AMD, including 68 who had an advanced stage of the disease, which can lead to severe vision impairment or blindness. In the United States, AMD is the major cause of blindness in whites, according to background information in the news release.

Prior evidence suggested that dietary zinc is similarly protective against AMD, so the researchers looked to see if zinc consumption from a diet of oysters and crabs reduced risk of AMD, but no such association was seen. However, the study authors theorized that the low dietary zinc levels relative to zinc supplements could account for the absence of such a link.

Anand Swaroop, chief of the neurobiology, neuro-degeneration, and repair laboratory at the U.S. National Eye Institute, interpreted the findings with caution. “It does make huge sense theoretically,” he said. “Photoreceptors have a very high concentration of a specific type of fatty acids and lipids, relative to many other cell types. So it would make sense that omega-3 consumption would be beneficial. The theory is sound.”

“However, I wouldn't want people to start taking grams of omega-3 to protect against AMD based on this finding because I'm not really sure that this study has sufficient power to draw any conclusions,” Swaroop added. “This is just a one-year analysis and AMD is a long-term disease. The correlation is important, and it should be explored further. But we need larger studies with longer term follow-up before being able to properly assess the impact.”

SOURCE: Anand Swaroop, Ph.D senior investigator and chief of neurobiology, neurodegneration, and repair laboratory, U.S. National Eye Institute, Bethesda, Md.; American Academy of Ophthalmology, news release, Dec. 1, 2010

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Obesity may interfere with Vitamin D absorption

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The more obese a person is, the poorer his or her vitamin D status, a new study by a team of Norwegian researchers suggests. The study found an inverse relationship between excess pounds and an insufficient amount of vitamin D, which is critical to cell health, calcium absorption and proper immune function. Vitamin D deficiency can raise the risk for bone deterioration and certain types of cancer.

The researchers also suggest that overweight and obese people may have problems processing the vitamin properly.

The team noted that after the so-called “sunshine vitamin” is initially absorbed (through either sun exposure or the consumption of such foods as oily fish and fortified milk), the body must then convert it into a usable form, called 1,25-dihydroxyvitamin D. This conversion process, however, seems to be short-circuited among obese people, complicating efforts to gauge their true vitamin D health.

The findings are published in the January issue of the Journal of Nutrition.

To investigate the impact of obesity on vitamin D absorption, the team spent six years tracking 1,464 women and 315 men, with an average age of 49. Based on the participants' body mass index (BMI), an indicator of body fatness calculated from a persons weight and height, the average participant was deemed to be obese. About 11 percent were categorized as “morbidly obese.”

From the outset, overall vitamin D levels were found to be below the healthy range, the authors noted. By the end of the study, overall levels of vitamin D were found to have dropped off “significantly” while BMI readings rose by 5 percent.

The research team concluded that having a higher-than-normal weight, body fat and BMI was linked to a poorer vitamin D profile. For example, people with the lowest BMI readings had 14 percent higher vitamin D levels than those with the highest BMI readings. Because vitamin D levels did not correlate properly with 1,25-dihydroxyvitamin D levels (and in fact appeared to have an abnormal inverse relationship), the authors suggested that future efforts to explore vitamin D status among obese people should test for both measures of vitamin D health.

They also suggested that people who are overweight and obese might benefit from vitamin D supplementation and more exposure to sunlight.

SOURCE: Journal of Nutrition, news release, Dec. 14, 2010

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A Whey to Reduce High Blood Pressure

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Supplementing diet with whey-based protein may help reduce high blood pressure, a U.S. researcher says.

Nutritional biochemist Susan Fluegel of Washington State University in Spokane says daily doses of commonly available whey brought a more than 6-point reduction in the average blood pressure of men and women with elevated systolic and diastolic blood pressures. Whey is a by-product of cheese-making. “One of the things I like about this is it is low-cost,” Fluegel says in a statement. “Not only that, whey protein has not been shown to be harmful in any way.”

The study, published in International Dairy Journal, finds not everyone drinking the whey-supplemented drink has changes in blood pressure.

The supplement did not lower the blood pressure of subjects who did not have elevated pressure to begin with. That's good, says Fluegel, since low blood pressure can also be a problem. However, blood-pressure reductions — as seen in those with elevated pressure in this study — can bring a 35 percent to 40 percent reduction in fatal strokes, says Fluegel.

Fluegel and colleagues looked at 71 student subjects ages 18-26, but Fluegel says older people with blood pressure issues would likely get similar results. The supplement was delivered in fruit-flavored drinks developed at the university's creamery.

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Vitamin D affects more than 200 genes

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Working in the laboratory, the scientists isolated fragments of DNA in cells to study the effects of exposure to calcitriol, the “active” form of vitamin D. Their findings are published in the journal Genome Research.

Vitamin D influences DNA through a “go-between” protein called the vitamin D receptor (VDR). The protein is activated by the vitamin and attaches itself to DNA at the binding sites the researchers identified. VDR binding was enriched in disease-associated regions of the genetic code and also areas linked to traits such as tanning, height and hair colour.

Study leader Dr Sreeram Ramagopalan, from the Wellcome Trust Centre for Human Genetics, at Oxford University, said: “There is now evidence supporting a role for vitamin D in susceptibility to a host of diseases. Vitamin D supplements during pregnancy and the early years could have a beneficial effect on a child's health in later life. “Some countries, such as France, have instituted this as a routine public health measure.”

Vitamin D is chiefly made in the body as a result of the skin's exposure to sunlight. A small number of foods also contain the vitamin, including oily fish and eggs, but 90% comes from being in the sun. In many northern countries, a lack of sun can lead to vitamin D deficiency. Over-zealous use of sunscreen can also prevent vitamin D production. It is estimated that more than half the UK population do not get enough vitamin D, and worldwide a billion people may be deficient in the vitamin. Lack of vitamin D affects bone growth and development, leading to rickets in children and bone fractures in adults.

The study supports the theory that lighter, more sun-sensitive skins evolved as people migrated north out of Africa to maximise vitamin D production in the body. A significant number of the VDR binding sites were in DNA regions where genetic changes are commonly found in people of European and Asian descent.

“Vitamin D status is potentially one of the most powerful selective pressures on the genome in relatively recent times,” said co-author Professor George Ebers, also from the Wellcome Trust Centre for Human Genetics. “Our study appears to support this interpretation and it may be we have not had enough time to make all the adaptations we have needed to cope with our northern circumstances.”

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