Nutrient shortfalls have health consequences that could impact daily life and overall wellbeing. National nutrition surveys show shortfalls in intakes of many nutrients. About one-third of American adults fail to get their average daily requirement for vitamin C even though vitamin C is relatively easy to obtain from foods; low intakes can lead to poor energy levels and weakness. More than 90 percent of adults fail to get their average daily requirement of vitamin E and many fall short in other vitamins and minerals, which can impact immune function. More than two-thirds of women of childbearing age have low intakes of iron, which can impair cognitive function, physical capability and endurance.
Even the most conscientious consumers find it difficult to get all the nutrients they need from food alone. While dietary improvement is a desirable goal, changing dietary patterns is extremely difficult. On the assumption that it is better for people to obtain recommended amounts of vitamins and minerals than to limp along with low intakes, a multivitamin with minerals which can be purchased for less than a dime a day is an inexpensive and effective way to fill a number of known nutrient gaps…
Dietary supplements are used by the majority of adults in the United States. More women than men use them; use also increases with age and education. Health professionals are just as likely as members of the general public to use supplements regularly. Supplement use should be seen as one component of the search for a healthier lifestyle, including improvements in overall food habits and engaging in physical exercise. While much of the current research on nutrition and health focuses on the prevention of chronic disease, the primary reason most people use multivitamins and other nutritional supplements is to support overall wellness.
A generous intake of calcium plus vitamin D demonstrably helps build optimum bone mass during childhood and adolescence and also slows the rate of bone loss that naturally occurs with aging. National surveys show that US calcium and vitamin D intakes are below recommended levels, especially for women – despite the fact that substantial research has shown supplements of calcium and vitamin D to be effective in maintaining or increasing bone density and potentially in protecting health in other ways as well.
Nutritional supplements are similarly helpful in addressing a woman’s increased nutrient needs during pregnancy. Prenatal multivitamins with minerals are commonly prescribed to ensure that both the baby’s and the mother’s needs are met. In addition to meeting normal nutritional needs during pregnancy, a multivitamin can also play a critical role in protecting against some birth defects. An abundance of data shows that women who get 400 mcg of supplemental folic acid per day for one to three months prior to conception and one to three months after conception can substantially lower the risk of having a baby with a neural tube defect such as spina bifida. In most studies demonstrating these results, the protective amount of folic acid was consumed in the form of a multivitamin supplement.
While adequate nutrient intake is critical for all age groups, it may have particular significance for the elderly. Antioxidant supplements have been shown to have a positive impact on eye health and cognitive function. Adequate nutritional status also affects the condition of the skin and supports lung and muscle function. Calcium and vitamin D supplements, as previously noted, can have a powerful impact on bone health, and the Surgeon General says it is never too late to benefit from improved intakes of these nutrients. Vitamin D may also reduce the incidence of falls in older people. Vitamin and mineral supplements have been shown in some studies to improve immune function in the elderly. Low zinc intakes are associated with an increased risk of infections, including pneumonia. Supplemental intakes of vitamin E have had a positive effect in decreasing upper respiratory infections in some studies. For these reasons, it makes sense to encourage the elderly to use multivitamin and mineral supplements. Some experts have also advocated providing a basic multivitamin and mineral supplement to the elderly in nursing homes, as a matter of policy, to avoid risking the consequences of inadequate intakes.
Traditional models of health and nutrition were focused on dietary improvement and nutritional adequacy. Good dietary patterns and adequate nutrient intakes based on the Recommended Dietary Allowances were considered the best guides to health, but chronic disease prevention through dietary modification was not a common topic of discussion. This focus changed dramatically in the 1980s following the publication of numerous reports suggesting a direct relationship between dietary factors and the incidence of numerous “killer diseases.”
The reports asserted that improved dietary patterns, including increased intakes of fruits, vegetables and whole grains, could reduce the risk of chronic disease. They also discussed which components of these foods were likely to be most protective, including fibre and a number of antioxidant nutrients. The reports emphasized the importance of improved food habits and downplayed the importance of increasing the intake of specific nutrients, but at the same time numerous clinical trials were undertaken specifically to evaluate the possibility that supplementation with some of the individual nutrients (especially antioxidants) might reduce the risk of cancer and heart disease.
While countless epidemiological trials support the hypothesis that dietary improvement can reduce the risk of chronic disease, the design of clinical trials to test that hypothesis is a challenge. Nevertheless, many clinical trials have in fact demonstrated benefits against disease for specific nutrients – for example, calcium to protect against osteoporosis, folic acid to help prevent some birth defects, and omega-3 fatty acids to reduce the risk of heart disease.
Excerpted from The Benefits of Nutritional Supplements (Fourth Edition) compiled by Annette Dickinson, Ph.D. Annette Dickinson worked in Washington, DC, for over 30 years for the Council for Responsible Nutrition (CRN). She is currently a consultant to CRN and other clients on nutrition issues and dietary supplement regulation and is also an Adjunct Professor in the Department of Food Science and Nutrition at the University of Minnesota.
What do essential nutrients actually do?
The functiocns of vitamins and essential minerals are well known and each of them plays one or more key roles in maintaining the daily functions basic to health and life itself. These functions are accomplished in every cell and every organ of the body, every minute of every day, from birth to death.
Some of these functions may ultimately provide some protection against chronic diseases such as cancer and heart disease. However, it is their more mundane but vital roles in metabolism that cause vitamins and minerals to be defined as “essential nutrients.” The following is intended as a simplified reminder of the immense scope of these basic functions.
Vitamins and essential minerals are components of enzymes and cofactors the body needs to accomplish the everyday miracles of constantly keeping the heart beating, the blood flowing, the muscles flexing, the bones strong, the digestive system churning efficiently, the cells dividing, the eyes sparkling, the skin protecting our outer and inner surfaces, countless membranes controlling what goes into and out of every cell and tissue, the kidneys filtering the blood and adjusting blood pressure, the lungs drawing in life-giving oxygen and expelling other gases, the nerves snapping and the brain cogitating.
The collective magnitude of these activities is illustrated by the fact that a large fraction of the body’s total energy expenditure is devoted to maintaining these functions. This portion of the total daily energy requirement is known as the basal metabolic rate (BMR), and it accounts for 50 to 70 percent of the body’s total daily energy expenditure.
The essential nutrients are critical to the performance of these functions. An essential nutrient is a substance the body must have in order to function, but which it cannot make for itself. Therefore, the nutrient must be obtained from outside sources, namely foods. There are 13 vitamins (which by definition are essential), 15 essential minerals or electrolytes, nine essential amino acids and a couple of essential fatty acids.
Given an adequate supply of calories (from a mixture of fats, carbohydrates and protein) and plenty of water, the body can use these essential nutrients to mix and match the various other components of foods and turn them into its own personal energy supply as well as continually creating new cells and tissues, blood and bone, muscles and brain, skin and hair. The essential nutrients in many cases are the catalysts or cofactors that make these operations possible.
The cells in the adult body are not the ones we were born with, since all of the body cells and tissues are constantly turning over – being worn out and repaired or replaced with new ones. Some tissues, like the cells lining the intestinal tract, turn over very rapidly – about every three days. The red blood cells turn over about every 120 days and newly manufactured ones continually take the place of the old ones. Some other body cells and tissues may last for years, but even those are subject to constant repair.
Needless to say, any fault or faltering in these processes could have a direct impact on the body’s ability to function. The nature of the impact will depend on which nutrients are in short supply and what tissues are affected.
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