4 vitamins essential to any diet

Vitamins are essential to our survival, but it can be challenging to get the right amounts. Here are four vitamins every diet needs, and how to get the amount you need.

•  There are several forms of this vitamin. The preformed, or active, ones are retinol, retinoic acid and retinyl esters. Beta-carotene is a precursor form.
• In general, vitamin A supplementation is not recommended. Excessive vitamin A can cause toxicity, which can lead to death in extreme cases.
• A woman contemplating pregnancy should never take high-dose vitamin A supplements.
• Because vitamin A is stored in the body, supplements should be stopped at least three months before attempting to conceive.
• Vitamin A is essential to normal vision and to prevent night blindness.
• It's also necessary for normal cell division and growth, the development of bones and teeth, the health of skin and much more.
• Vitamin A's antioxidant properties help prevent the cancer-causing cell damage inflicted by free radicals, unstable molecules that are released when the body uses oxygen.
• The body also needs vitamin A to synthesize amino acids, thyroxine and other hormones.

•  There are two forms of this vitamin: D2, which comes from plants, and D3, which the body synthesizes when the skin is exposed to ultraviolet (UV) rays from the sun.
• No matter how much sun you get, however, your body can't produce Vitamin A during winter in northern areas.
• The body must have vitamin D in order to absorb calcium.
• Vitamin D also promotes absorption of phosphorus and prevents the kidneys from excreting protein in the urine.
• Because of its role in mineral absorption, vitamin D promotes the growth of strong bones and teeth.
• A deficiency causes rickets in children and osteomalacia in adults.

• The tocopherols in vitamin E prevent oxidation. This results in the rancidity of fats and the destruction of vitamins A and D.
• Tocopherols also help to maintain healthy red blood cells and muscle tissue, protect the lungs from pollutants and regulate the synthesis of vitamin C and DNA.
• Researchers are still exploring the relationship between vitamin E and heart disease prevention.

• Your liver needs vitamin K to manufacture blood proteins that are essential for blood clotting.
• Intestinal bacteria make half the needed vitamin K. The rest comes from the diet.
• New research suggests that vitamin K might play a role in maintaining strong bones in adults.
• Studies suggest that it may increase bone density and also reduce fracture rates.
• Studies have found that people who consume the most vitamin K have a lower risk of hip fractures than those who consume less.
• Not having enough vitamin K can cause excessive bleeding, even from minor cuts.
• Some newborn infants are especially vulnerable to vitamin K deficiency, because they lack the intestinal bacteria needed to make it.

Vitamin deficiency can be dangerous for people of all ages. Your climate and diet all contribute to your vitamin levels. If you're experiencing a vitamin deficiency, talk to your doctor about supplements or lifestyle changes that could help you stay healthy.