Vitamins: What, Why and How: One of the Essential Nutrients for Good Health (#4 in series)
You need 7 nutrients in your diet to prevent disease and maintain good health. They are carbohydrates, proteins, fats, fiber, vitamins, minerals and water.
Vitamins are your micronutrients and your body need them in small quantities. Minerals are your other micronutrients. Individual Minerals will be discussed serpartly.
Last week you learned about dietary fats which is one of your macronutrients. Protein and carbohydrates are your other macronutrients. If you missed them, here they are:
Micronutrients:
Before going into individual vitamins, there are some general distinctions and relationships between the two groups of micronutrients you should know.
The major difference between vitamins and mineral is that vitamins are organic (contain carbon) and minerals are inorganic (does not contain carbon). This means that vitamins can breakdown due to heat, air, or acid, while minerals will hold on to their chemical structure.
This makes vitamins more fragile and their content can vary depending on cooking methods, storage and exposure to light or air. Minerals, on the other hand, can get into your body from the soil or water your food came from
Like most thing in your body, balance is key. Adequate amounts allow vitamins and minerals to interact positively- Vitamin D enables your body to absorb calcium from your food and not your bones.
While an imbalance or too much of one can negatively affect another- too much of magnesium can effect iron absorption and lead to anemia.
Deficiencies in vitamins or minerals can cause specific diseases or conditions over time, while an overdose can literally poison your body.
Vitamins:
Vitamins are classified as water soluble and fat-soluble. Your water-soluble vitamins include B vitamins (B complex) and vitamin C. Your fat-soluble vitamins include A, D, E and K.
Your B complex vitamins are actually comprised of eight different vitamins. They are B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6, B7 (biotin), B9 (Folic Acid) and B12 (1).
All B vitamins help the body convert food (carbohydrates) into fuel (glucose), which is used to produce energy. B vitamins also help the body use fats and protein. They also help the nervous system function properly (2).
B12 is especially needed for maintaining healthy nerve cells because it helps in the production of DNA and RNA, your body's genetic material. Without or with low levels of B12 other reactions can’t occur needed for DNA and RNA synthesis or making.
Another vital function of Vitamin B 12 is its role in maintaining the health of your myelin sheath that insulates your nerve fibers. Nerve fibers are just the long tail part of a nerve cell. Some of these tails are quite long and can run from head to toe.
B12 is only found in animal products. Plants do not make vitamin B12. Vegetarians need to look for fortified foods to meet their B12 needs. Foods fortified with B12 include some plant milks, soy products and breakfast cereals (3).
It is rare to find a young health person with B12 deficiency, but as you age your ability to absorb B12 may decrease. Some illnesses, diseases and medications also may prevent absorption- like Pernicious anemia and Crohn disease.
Folate (B9) is important in the prevention of birth defects and adequate amounts should be reached prior to pregnancy. This is because spinal cord development happens early in pregnancy many times before the mother may know she is pregnant.
The FDA requires that folic acid be added to most enriched breads, flour, cornmeal, pastas, rice, and other grain products to help us get enough folate. Doctors usually recommend woman of child bearing age take additional folate (4).
B complex vitamins, especially vitamins folate (B9), B6, and B12, help lower homocysteine (a protein) levels. High levels of homocysteine levels are suggested to increase risk of cardiovascular disease and stroke, but the research is not conclusive (5).
Vitamin C is a water soluble vitamin that has a number of functions in your body. Its primary function is as an electron donor. As an electron donor, vitamin C is a potent antioxidant your body. It protects your cells and keeps them healthy from free radicals damage.
The body also needs vitamin C to make collagen, a protein that helps with wound repair and the structure of your skin. You will see many topical creams with vitamin C in them for this reason. There is evicence to support vitamin C in skin creams does benefit your skin (6).
In addition, vitamin C improves the absorption of iron from plant-based foods and helps the immune system work properly to protect the body from disease.
There are many claims that vitamin C helps with depression, cancer, cardiovascular disease and can reduce tiredness and fatigue. The evidence is quite persuasive, but not conclusive according to the FDA (7). However, the European Food and Safety Authority (EFSA) believes these relationships do exist (8). It is best to consult your health care provider.
Foods rich in vitamin C include bell peppers, dark leafy greens, kiwi fruit, broccoli, berries, citrus fruits, tomatoes, peas, and papayas.
Vitamin D is a fat soluble vitamin. It has the nickname as “the sunshine vitamin,” because your body can convert ultraviolet rays (UVB) from sunlight to vitamin D.
Few foods are naturally rich in vitamin D, so fortified foods are your biggest source of vitamin D. Good sources include dairy products and breakfast cereals (both are fortified with vitamin D), and fatty fish such as salmon and tuna.
Vitamin D helps ensure that the body absorbs and retains calcium and phosphorus, both critical for building bone. Without adequate levels of vitamin D, levels of calcium and phosphorus surfer- overtime this could result in osteoporosis (9).
Osteoporosis is when the bone has become brittle and frail. It is due a decrease in bone mineral density. The spongy bone or trabecular bone found at the end of your long bones becomes porous. This makes them weak and prone to fracture. It is a growing concern for older adults (10).
Vitamin D sufficiency prevents rickets in children and osteomalacia in adults- conditions that lead to soft bones. Both conditions are results from a defect in the mineralization of the protein framework or building process. The cause of rickets or osteomaliacia is usually insufficient Vitamin D which prevents the normal mineralization of calcium and phosphorous to build strong bones.
Other deficiencies in vitamin D have been linked to muscle weakness, heart dysfunction, certain cancers and impaired immune function. Most of your organs and tissues have receptors for vitamin D. Scientists are still testing the possible role vitamin D plays in these areas (11).
Currently there are four studies around the world looking at vitamin D. One of the bigger studies is right here in Boston. It is called the VITAL study. You should have more conclusive answers in three years.
There is conflicting data on the prevalence of vitamin D deficiency in the US. Some experts will report up to two-thirds of Americans are Vitamin D deficient, while other will say it is a low as 27% (12, 13).
The experts do agree that people with darker skin are at a greater risk of vitamin D deficiency. This is because the same skin pigment that protects them from burning prevents vitamin D absorption from the sun. Sunscreen will have the same affect.
As you age your ability to absorb vitamin D from the sun and food sources will decrease -for this reason the vitimin D guidline increases past the age of 70.
Here are the Institute of Medicine guidelines for calcium and vitamin D.
Currently, vitamin D status is not tested in route blood exams. Your doctor would have to request it and insurance may not pay for it.
Vitamin E is a fat soluble vitamin known for its antioxidant properties. It prevents free radical damage which can harm cells, tissues, and organs. Free radicals are believed to play a part in aging and linked to a number of chronic diseases such as CVD and cancer. Vitamin E does support your immune function.
There are eight different forms (isomers) of vitamin E: alpha-, beta-, gamma-, and delta-tocopherol; and alpha-, beta-, gamma-, and delta-tocotrienol. In your body Alpha-tocopherol is the most active form.
Deficiencies in vitamin E are rare in healthy adults. It may be seen in people with limited fat absorption due to surgery, Crohn's disease, or cystic fibrosis.
Food sources of vitamin E include vegetable oils (corn, cottonseed, safflower, soybean, sunflower), olive oil, eggs, fortified cereals, fruit, green leafy vegetables (such as spinach), meat and nuts.
Cooking and storage may destroy some of the vitamin E in foods (14).
There are actually two forms of Vitamin A in your diet. Preform Vitamin A and provitamin A (carotenoids).
Preform Vitamin A is found in animal sources like fish and meat (especially liver). Provitamin A is found in the pigments of plants. Your body converts these plant pigments into vitamin A. The most important form of provitamin A is beta-carotene.
Beta-carotene is an antioxidant. It protects your from free radicals. Over time, free radicals can damage your cells that can lead to a number of chronic illnesses. There is good evidence that eating more antioxidants from foods helps boost your immune system, protect against free radicals, and may lower your risk of heart disease and cancer.
There is no evidence that the same benefits are gained though supplementation of beta-carotene. Research done on supplementing with beta-carotene has been shown an increased risk of lung cancer and cardiovascular disease. Instead, you should consume a combination of colorful fruits and vegetables ("eat the rainbow"). They do not have the potential risks and are better for you. Leafy green vegetables, orange and yellow vegetables, tomato products, fruits are good sources of beta-carotene (15).
Vitamin A can be toxic. Too much preform vitamin A can lead to liver damage, birth defects and decrease bone mineral density. Most of the toxicity is due over supplementation and not from food. You should consult a medical professional before taking any supplemental form of vitamin A (16).
Vitamin k primary role in the body is assisting with normal blood clotting. It is also involved in bone health. Vitamin K prevents severe blood loss in an injury by slowing down and stopping bleeding.
Food sources rich in Vitamin K include: spinach, broccoli, iceberg lettuce, and fats and oils, particularly soybean and canola oil.
Most American diets contain an adequate amount of vitamin K.
Warfarin (Coumadin®) and some anticoagulants interfere with the activity of vitamin K. For this reason, individuals who are taking these anticoagulants should consult their health care professional for dietary advice.
Next week you will learn the other micornutrient- minerals.
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