Vitamin A is a fat-soluble vitamin that exists in two forms in nature. First there is the real form, also called retinol, which exists in animal products like fish-oil and liver. This form can easily be used by the human body and is stored and released by the liver.
The second form called beta carotene, or provitamin A, exists in vegetables and is the precursor to vitamin A. The human body cannot directly use beta carotene as vitamin A, but needs to transform it into retinol using fats and gal. That’s why it’s advisable to always put a little oil on your salad. Beta carotene is part of the carotenoid family, whose members include lycopeen, alfa carotene, lutein and zeaxanthine. Carotenoids can absorb dangerous solar rays and act as anti-oxidants.
Normal healthy people only transform about 25% of consumed beta carotene into vitamin A.
Being a fatty acid it is advised to take some vitamin E together with vitamin A, to prevent oxidation.
Benefits: Vitamin A helps to prevent colds and infections, primarily of the mucosa of the eyes, ears, nose, throat, lungs and bladder. Vitamin A is needed for forming the pigment in the eyes that is needed to see at night. Also it prevents kidney stones. Some studies have shown that carotenoids have protective properties against some forms of cancer.
Best natural sources: codfish-oil, animal liver, carrots, pumpkins and other yellow vegetables, yellow fruits like apricots, peaches, papaya’s and cantaloupes, eggs, milk and dairy products
Recommended daily dosages: Adults 1000 micrograms, children 700 micrograms. Since vitamin A is fat-soluble, excess intake is stored in the liver and body fat , so it not recommended to take too high dosages, especially over a longer period. It is better to take beta-caroteen and let the body transform it into vitamin A as needed. Also you will have the benefit of beta-carotenes anti-oxidant effects.
All members of the vitamin B-complex are water soluble. So far 16 B-vitamins have been isolated. Together they are called the vitamin B-complex, because they are found together in animal products and vegetables. Vitamins from the B-complex are of crucial importance for the process of transforming carbohydrates into glucose and from food to energy. When the body has a shortage of vitamin B the burning of carbohydrates is not complete and that can cause symptoms like nervousness, constipation, fatigue and indigestion. B-vitamins have a lot of effects from relieving stress to preventing arteriosclerose.
It is important to ingest the entire vitamin B-complex, because there functioning depends on each other. Excessive consumption of one B vitamin can disturb the vitamin B balance and cause shortages of others. For example people taking vitamin B6 supplements for burning more fat are at risk and it is advisable to take complete vitamin B-complex supplements instead.
Benefits: The vitamin B-complex helps to enforce the nervous system. People under a lot of stress can have benefit from consuming products like liver and brewers yeast. B vitamins can also have benefit for people with weak digestion, loss of appetite, constipation, fatigue, amenia or migraines. Some B-vitamins can even help prevent the greying of hair.
Best natural sources: Organ meat (especially liver), brewers yeast, whole wheat grains, brown rice
Recommended daily dosages: Although some functions of B-vitamins overlap, they all have their own qualities and cannot replace each other. Because B-vitamins are water soluble, B-vitamins that are not needed are excreted, so there is hardly any chance of overdose.
Vitamin C, or ascorbic acid, is another water soluble vitamin. Vitamin C is very instable and breaks down easily by cooking, but also by peeling the fruits and vegetables that contain them. Vitamin C is usually found together with other nutrients called bioflavonoids, also called vitamin P. They support the functions of vitamin C and increase its effectiveness.
Vitamin C influences several other nutrients. It improves the adsorption of calcium and iron by the body and helps to remove toxic copper, lead and mercury from the body. And it aids in the adsorption of certain amino acids and is needed in large quantities to help digest protein rich foods.
The most well know disease the is caused by lack of vitamin C is scurvey. Although scurvey is still found in areas of famine, symptoms can also be found in people who primarily survive on junk food.
Humans are one of the few mammals who cannot make vitamin C themselves, so we need to ingest all our vitamin C through our food. Because it’s water soluble and very instable, it quickly disappears from the body. That’s why humans need a steady stream of vitamin C throughout the day. Also smokers need more vitamin C than non-smokers, because a cigarette destroys about 25 mg of vitamin C.
Benefits: There is a strong consensus between nutritionists that vitamin C is useful for combating the common cold. Dr. Linus Pauling, a winner of the Nobel price, published a paper called ‘Vitamin C and the common cold’, bringing the use of megadoses of vitamin C into the public arena. Vitamin C is useful on many fronts besides preventing scurvey. It’s an anti oxidant that delays aging. As an antihistamine it alleviates allergies and as an anti pollutant it helps to eliminate toxics from the body.
One of the most important biologic functions of vitamin C is to help the formation of collagen (the ‘cement’ of the skin). Lack of collagen in the skin can be the cause of wrinkles. Vitamin C increases our immune reaction to infectious diseases by increasing the production of certain immune cells. Vitamin C speeds up the healing of wounds and makes the bloodvessels stronger, which can prevent strokes. Certain studies have shown that vitamin C can reduce cholesterol levels. And vitamin C can give extra protection against the devastating effects of smoking and alcoholism by reducing the toxic byproducts.
Best natural sources: Whole citrus fruits and citrus juices, peppers, broccoli, tomatoes, cabbage, green leaf vegetables, melons, yams, patatoes
Recommended daily dosages: Adults and teenagers 70 mg, children (up to 10) 50 mg. In light of recent studies the recommended daily dosage is quite low. Even though it prevents scurvey, it doesn’t improve general health and the immune system. Nutrition specialists recommend several grams of vitamin C per day. Based on a study on animals which synthesize their own vitamin C dr. Linus Pauling concluded that humans need 1,5 to 4,0 grams of vitamin C per day.
Vitamin D is a fat soluble vitamin that we ingest through our food or by exposure to sunlight. Vitamin D that is produced in our skin by exposure to ultra violet sunlight is absorbed directly into the bloodstream. Ingested vitamin D gets absorbed in the intestines. Absorbed vitamin D is primarily stored in the liver, but also in small amounts in the skin, brains and bones. People who don’t drink milk or who are strict vegetarians might be concerned with their vitamin D intake.
Vitamin D is hardly present in vegetables. People who work indoors should also be concerned about their vitamin D intake. One thing to realize is that a skin that is brown for tanning also stops producing vitamin D at a certain point. Being a fat soluble vitamin one should be careful with supplements though.
Benefits: Vitamin D improves the absorption of calcium and phosporus, which are of vital importance for strong bones and teeth and to prevent rachitis (english disease). Vitamin D helps to assimilate vitamin A and guards a healthy nervous system, normal heart rate and efficient blood coagulation.
Best natural sources: Cod liver oil, sardines, herring, salmon, tuna, enriched milk
Recommended daily dosages: Adults and teenagers 2,5 - 10 micrograms, childeren (up to 10) 10 - 15 micrograms. Take note that daily overdoses of 50 micrograms and more can lead to excessive storage of vitamin D in the body and can lead to symptoms of vitamin D poisoning like diarrhea, nausea, excessive urination, calcification of the arteries and kidney damage.
Vitamin E is also a fat soluble vitamin. Vitamin E is actually a group of substances called tocopherols, which are divided in alpha, beta, gamma, etc. Of all the tocopherols alpha-tocopherol is the most chemically active. Tocopherol is derived from a Greek word that means ‘to give birth’. This is because the first studies into vitamin E were concerned with fertility.
Vitamin E is a very strong anti oxidant. Vitamin E binds with oxygen to prevent the formation of destructive free radicals. Free radicals can have many destructive effects in the body, for example they cause damage to brain cells, weaken the immune system and cause damage to the DNA.
Some substances, like oxygen, iron, pills containing oestrogen, chloride and mineral oils, make vitamin E ineffective. Inorganic iron, like ironsulfate, destroys vitamin E, while organic iron, like irongluconat does not. So vitamin E should not be taken at the same time as inorganic iron.
Oestrogen can neutralize vitamin E. This gives rise to the thought that the side effects of birth control pills can be the result of a lack of vitamin E. Also people who live in areas with very polluted air or whose water is rich in chlorine should consider taking vitamin E supplements.
In two studies at Harvard University is was shown that people who took vitamin E supplements of 100 IE for at least two years had a 40% less chance of heart disease than people who did not take extra vitamin E. Also in several studies it has been concluded that the chance of cancer is higher in people who have very low vitamin E intake.
Benefits: Vitamin E supports cell regeneration and delays the aging process, because of its anti oxidant qualities. Vitamin E protects fat soluble vitamins and hormones and in high dosages it protects against the consequences of pollutants in food, water and air. Vitamin E helps to lower blood cholesterol levels and thins the blood. This helps to prevent blood clotting and flebitis.
Vitamin E plays an important role in the fight against all the primary causes of death in our western society, heart disease, cancer, diabetes, accidents, including burns. Using vitamin E against burns helps against to forming of blisters and scars.
Vitamin E also has beneficial effects on fertility and sexual potency. Vitamin E is also involved in the production of chemicals that transport nerve impulses to our muscles and therefore can be useful with chronic degenerative diseases like multiple sclerosis.
Best natural sources: Raw wheat germs and wheat germ oil, vegetable oils, soybeans, green leaf vegetables, whole grains and cereals, eggs
Recommended daily dosages: Adults 20 mg, children and teenagers 0,8 mg. Most nutrition specialists recommend higher dosages.
Vitamin K is another fat soluble vitamin, that exists in three forms, namely K1, K2 and K3. K1 en K2 are synthesized by the intestinal bacteria. Synthetic vitamin K3 is available for those who cannot make K1 and K2 themselves.
To ensure a good vitamin K supply from the intestinal bacteria, one should eat dairy products like yogurt and buttermilk daily. Excessive consumption of sugar and products containing sugar should be avoided. Antibiotics which kill good and bad bacteria in the body are antagonistic to vitamin K and should be avoided. If you do need to use them, eat extra yogurt or buttermilk to reduce the destructive effects.
Benefits: The liver needs vitamin K to produce prothrombin, one of the many factors that play a role in the coagulation of the blood. Vitamin K is therefore important for the prevention of internal bleedings. Vitamin K also helps to prevent thrombosis.
Best natural sources: Luzerne (alfalfa), green leaf vegetables, kelp, yogurt or buttermilk, egg yolk, cod liver oil, safflower and soy oils
Recommended daily dosages: there is no official recommended dosage for adults. Children (up to 10) 25 micrograms, teenagers 35 micrograms.
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