Zinc May Help School Students' Thinking

FOXNews.com - Health - Zinc May Help Middle School Students' Thinking: "Better Thinking With Zinc?

First, the students 111 girls and 98 boys took tests covering mental skills like memory, attention, perception, and reasoning. Their teachers also gauged the students behavior in class.



Next, the students drank fruit juice containing 0, 10, or 20 milligrams of zinc each school day for 10 weeks. After 10 weeks, they retook the tests and the teachers reviewed student conduct again. The U.S. recommended dietary allowance for zinc in adolescents ranges from 9-11 milligrams per day.



The seventh-graders who took 20 milligrams of zinc fared best. Their reaction times on a visual memory test became 12 percent quicker, their scores on a word recognition test improved by 9 percent, and their results on a task requiring sustained attention rose by 6 percent.



The placebo group also improved, but their gains were smaller. Their reaction times fell 6 percent on the visual memory test, their word recognition test scores increased by 3 percent, and their results on the attention-based test inched up by 1 percent.



Young adolescents may benefit from increased zinc intakes and underscore the need to further determine the functional roles of zinc nutrition in older children,the researchers write.

The findings were presented at Experimental Biology 2005, a conference being held in San Diego.



By Miranda Hitti, reviewed by Brunilda Nazario, MD



SOURCES: Experimental Biology 2005, San Diego, April 2-6, 2005. News release, Federation of American Societies for Experimental Biology. Clinical Nutrition Service, Office of Dietary Supplements, National Institutes of Health, “Facts About Dietary Supplements: Zinc.” Linus Pauling Institute.

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Problems with Fructose and insulin resistance

Nutrition & Metabolism | Abstract | Fructose, insulin resistance, and metabolic dyslipidemia: "Fructose, insulin resistance, and metabolic dyslipidemia

Heather Basciano , Lisa Federico and Khosrow Adeli

Clinical Biochemistry Division, Department of Laboratory Medicine and Pathobiology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada



Nutrition & Metabolism 2005, 2:5 doi:10.1186/1743-7075-2-5 Published 21 February 2005



Abstract



Obesity and type 2 diabetes are occurring at epidemic rates in the United States and many parts of the world. The 'obesity epidemic' appears to have emerged largely from changes in our diet and reduced physical activity. An important but not well-appreciated dietary change has been the substantial increase in the amount of dietary fructose consumption from high intake of sucrose and high fructose corn syrup, a common sweetener used in the food industry. A high flux of fructose to the liver, the main organ capable of metabolizing this simple carbohydrate, perturbs glucose metabolism and glucose uptake pathways, and leads to a significantly enhanced rate of de novo lipogenesis and triglyceride (TG) synthesis, driven by the high flux of glycerol and acyl portions of TG molecules from fructose catabolism. These metabolic disturbances appear to underlie the induction of insulin resistance commonly observed with high fructose feeding in both humans and animal models. Fructose-induced insulin resistant states are commonly characterized by a profound metabolic dyslipidemia, which appears to result from hepatic and intestinal overproduction of atherogenic lipoprotein particles.



Thus, emerging evidence from recent epidemiological and biochemical studies clearly suggests that the high dietary intake of fructose has rapidly become an important causative factor in the development of the metabolic syndrome. There is an urgent need for increased public awareness of the risks associated with high fructose consumption and greater efforts should be made to curb the supplementation of packaged foods with high fructose additives. The present review will discuss the trends in fructose consumption, the metabolic consequences of increased fructose intake, and the molecular mechanisms leading to fructose-induced lipogenesis, insulin resistance and metabolic dyslipidemia.

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More than just bones helped by Vitamin D

Low vitamin D levels may be cause of some health complaints so make sure you get your safe quota of sunshine.

By Pamela Stuppy

We hear a lot about concern about getting enough calcium for our bones, but vitamin D often takes a back seat when it comes to recommendations.
Vitamin D plays a crucial role in bone health. Not only can it reduce the risk of osteoporosis (bone brittleness), but can also reduce the chance of osteomalacia (a softening of bone). Vitamin D deficiency can draw calcium out of the bone.

Health-care professionals are starting to realize that some health complaints are related to low vitamin D levels. The aching bones and muscles, characteristic of a vitamin D deficiency, are often diagnosed as "growing pains" in children, fibromyalgia in adults, or trouble moving about by some nursing home patients.

Researchers and health care providers have identified a surprisingly high percentage of children and adolescents in the Boston area with vitamin D deficiencies. Many individuals in nursing homes and hospitals are also deficient.

What does vitamin D do?

One of its major roles is to absorb calcium from the intestinal tract into the bloodstream and move it from the bloodstream into the bones. It also helps regulate the excretion of calcium by the kidneys. When vitamin D levels are below normal, the uptake of calcium is reduced and bones are not maximally benefited.

Where do we get vitamin D?

Ultraviolet radiation from the sun reacts with our skin to create a precursor for active vitamin D. This precursor then goes through two activation stages, one in the liver and the other in the kidney. The final product is the form of vitamin D that can take action. Any interference with this process can reduce the level of vitamin D in the blood.

Sunscreen effectively blocks UV rays so the skin is unable to produce the vitamin. People with darker skin (which protects the skin like sunscreen) have more difficulty producing adequate vitamin D in most parts of the United States. Many African-Americans living in the northern parts of the country have been identified as vitamin D deficient. The farther away you get from the equator, the lower the level of UV exposure.

In New England, we can get vitamin D from the sun May through October (a good reason to head for a warmer climate on vacation in the winter!). A daily dose is about five to 10 minutes of hand and face exposure before applying sunscreen. This limits the concern of skin cancer from extended sun exposure, but allows for the needed production of vitamin D.

Older adults often have reduced levels because their skin produces D at only about 25 percent that of younger adults. They may also have less efficient livers and kidneys, tend to use more sunscreen, wear more clothing, and get outside less often. People with medical conditions that reduce nutrient absorption in the intestine (such as Crohn’s disease or untreated celiac disease), are also at risk for vitamin D deficiency.

Besides sunlight, the other sources of vitamin D are foods - generally those which have been fortified - or supplements. Food sources continue to change because of the current trend to add nutrients to much of our food supply. Milk, fish liver oils, and liver contain D, as well as some yogurt, orange juice, soy milk, cereals, and others.

The deficiencies seen in children and adolescents can be blamed on lower intakes of milk, the use of sunscreen, and/or more time spent indoors on the computer or watching television. Some children stay inside because of living in unsafe neighborhoods.

How much vitamin D do we need?

Recommendations vary depending on who you ask. About 200-400 IU is a general goal for most children, adolescents and adults. At about 50 years of age, intake should be at least 400 IU and over 70 years old, at least 600 IU. For people with osteoporosis or using a medication that depletes bone (like prednisone), intake should be at least 800 IU. If a person is on medication for osteoporosis, adequate intakes of both calcium and vitamin D are important so that the medication can be maximally effective.

However, some researchers believe that the recommendations for all age groups are much too low. They advocate taking a supplement above the level found in most multiple vitamins. Since it is a stored vitamin, people with diagnosed deficiencies are being treated under a physician’s care, to levels as high as 50,000 IU weekly, but blood levels need to be monitored.

Survey research shows that at least 90 percent of the U.S. population does not get adequate vitamin D. Obviously, some populations are at greater risk. Making sure you are getting adequate vitamin D is a good investment for your bones.


Pamela Stuppy, MS, RD, LD, is a registered, licensed dietitian with nutrition counseling offices in York, Maine, and at Whole Life Health Care in Newington. She is also the nutritionist for Phillips Exeter Academy.

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