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Zinc

Zinc formulations have been used since the time of Ancient Egyptians to enhance wound healing.  The clinical significance in human nutrition and public health was recognized relatively recently.  It’s deficiency in humans was first describes in 1961, when the consumption of diets with low zinc was associated with “adolescent nutritional dwarfism” in the Middle East.  Since then, the deficiency of zinc has been recognized by a number of experts as an important public health issue, especially in developing countries.

Zinc is also an essential trace element for all forms of life.  As it is necessary for the functioning of over 300 different enzymes and plays a vital role in an enormous number of biological processes.

Numerous aspects of cellular metabolism are zinc-dependant.  Zinc plays important roles in growth and development, the immune response, neurological function, and reproduction, in the structure of proteins and cell membranes.

The immune system is adversely affected by even moderate degrees of zinc deficiency.  It was found that severe zinc deficient depresses the immune function.  Zinc is required for the development and activation of T-lymphocytes, a kind of white blood cell that helps fight infection.  When zinc supplements are given to individuals with low zinc levels, the numbers of T-cells lymphocytes circulating in the blood increase and the ability of lymphocytes to fight infection improves.  Zinc supplements are often given to help heal skin ulcers or sores, but they do not increase rates of wound healing when zinc levels are normal.

There is no single laboratory test that adequately measures zinc’s nutritional status.  Medical doctors who suspect a zinc deficiency will consider risk factors such as inadequate caloric intake, alcoholism, digestive diseases, and symptoms such as impaired growth in infants and children when determining a need for zinc supplementation.  Vegetarians may need as much as 50% (1.8 mg/daily) more zinc than non-vegetarians because of the lower absorption of zinc from plant foods, so it is very important for vegetarians to include good sources of zinc in their diet.

Zinc is found in oysters, and to a far lesser degree, in most animal proteins, beans, nuts, almonds, whole grains, pumpkin and sunflower seeds.  A turkey’s neck and beef’s chunk or shank also contains significant amount of zinc.  Phytates, which are found in whole grain breads, cereals, legumes and other products, have been known to decrease zinc absorption.  Fortunately, a healthy diet can provide you with as much zinc as you need.  However, the truth of the matter is that only about 30% of the zinc that you intake can get absorbed by your body.

Chromium

Chromium is a mineral that humans also require in trace amounts, although its mechanisms of action in the body and the amounts needed for optimal health are not well defined.

Although trivalent chromium is recognized as a nutritionally essential mineral, scientists are not yet certain exactly how it functions in the body.

Chromium has long been of interest for its possible connection to various health conditions.  Among the most active areas of chromium research is its use in supplement form to treat diabetes, lower blood lipid levels, promote weight loss, and improve body compositions.

It is believed that chromium affects glucose metabolism by enhancing the effects of insulin.  Insulin is secreted be specialized cells in the pancreas in response to increased blood glucose levels, such as after a meal.  A decreased response to insulin or decreased insulin sensitivity may result in impaired glucose tolerance or type 2 diabetes.  However, the value of chromium supplements for diabetics is inconclusive and controversial.  Randomized controlled clinical trails in well-defined, at-risk populations where dietary intakes are known, are needed to determine the effects of chromium on markers of diabetes.

The effects of chromium supplementation on blood lipid levels in humans are also inconclusive.  The mixed research findings may be due to difficulties in determining the chromium status of subjects at the start of the trails and the researchers’ failure to control for dietary factors that influence blood lipid levels.

Some claim that chromium supplements reduce body fat and increase lean (muscle) mass.  Yet a recent review of numerous studies that examined the effects of 200 to1,000g/day of chromium on body mass or composition found no significant benefits.  Another recent review of randomized, controlled clinical trails did find supplement of chromium picolinate to help with weight loss when compares to placebos, but the differences where small and of debatable clinical relevance.

Chromium I widely distributed in the food supply, but most foods provide only small amounts.  Processed meats, whole grain products, ready-to-eat bran cereals, green beans, broccoli, and species are relatively rich in chromium; however the content of the mineral is substantially affected by agricultural and manufacturing process.

Absorption of chromium from the intestinal tract is low, ranging from less than 0.4% to 2.5% of the amount consumed, and the reminder is excreted through bodily waste.  Vitamin C and niacin might enhance the mineral’s absorption.  Absorbed chromium is then stored in the liver, spleen, soft tissue, and bone.

 

Until next time…Stay Healthy

  

Katarzyna

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