Both an excess and a deficiency is detrimental and harmful. Trace elements (or dietary minerals) and vitamins interact with each other and the way they work.

Vitamin A

Vitamin A is essential for vision (night blindness), growth and immune system. Vitamin A is found in our diet as carotene and retinol. Beta - carotene (from plants) acts as an antioxidant, retinol (animal) is toxic at excessive intake (would increase the risk of esophageal cancer).
Carotenes should reduce the risk of cancer, heart disease and heart attacks and cataracts.
Important food sources of beta - carotene are liver, fish, dark green leafy vegetables, turnips, deep orange or yellow fruits and vegetables (carrots, sweet potatoes, strawberries, squash, apricots, grapefruit, oranges,...).

vitamineralenVitamin B group (B1, B3, B5, B8, B11..)

The vitamins of the B group will ensure in particular the stability of the central nervous system. They would largely occur in whole grains, whole wheat bread, some nuts and seeds, fresh fruits and vegetables. Other good sources include almonds, walnuts, peanuts, sunflower seeds, sesame seeds, brewer's yeast.

Vitamin B2 (riboflavin)

Important for the nervous system, healthy skin, thyroid and digestive system. Dairy, meat, liver, legumes, seaweed, whole grains, sunflower seeds, brewer's yeast, green leafy vegetables, broccoli, asparagus, avocados and peas contain vitamin B.

Vitamin B6 (pyridoxine)

Vitamin B6 is important as a co- enzyme for the proper functioning of the nervous system. The more protein you eat, the more vitamin B6 the body needs.
Especially eggs, fish, chicken, corn, banana, whole grains are rich in this vitamin. Other sources include avocados, sweet potatoes, broccoli, cabbage, dried apricots, nuts (especially walnuts), wheat germ, sunflower seeds, lentils, peas and carrots.

Vitamin B12 (cobalamin)

Vitamin B12 is required for the production of blood cells and for the growth, to the nervous system and the brain cells. They are necessary for protein synthesis and metabolism of carbohydrates and fats.
Plants nor animals can create the vitamin, microorganisms such as bacteria, fungi and algae do. Plants can be contaminated with it, and herbivores so take it.

Folic acid (folacin)

Folic acid is required for the protein metabolism and cell division (DNA synthesis).
Good sources of folate include beans (red beans, soy beans, lentils, quaker peas, peas), whole grains, various vegetables, especially green leafy vegetables (spinach, cabbage, Brussels sprouts, romaine lettuce, cabbage lettuce), okra, sweet corn, pumpkins, beets and broccoli and blackberries, kiwis, oranges, plantains, strawberries, pineapple.

Vitamin C and B promote the absorption of folic acid, while alcohol, coffee and tobacco reduce the absorption. By preserving, boiling to much or decanting cooking water a significant portion of the folic acid in the food is lost.

fruitVitamin C (ascorbic acid)

Vitamin C is important for the transport of oxygen in the body and for the health of the connective tissues. It increases resistance to infections and strengthens blood vessels. Vitamin C is a classic antioxidant.
Very good sources of vitamin C are citrus fruits (oranges, lemons, limes), alfalfa sprouts, peppers, papaya, broccoli, blackberries and strawberries.
Due to hard boil vitamin C can be destroyed, and in preserved fruits and vegetables the amount of vitamin C is reduced.

Vitamin D
(cholecalciferol or D3 is synthesized in the body, ergosterol or D2 comes from plant sources.)

Vitamin D keeps the level of calcium in the blood levels, ensures strong bones and teeth, and good health and vitality in general. Vitamin D appears to be a hormone. Exposure to sunlight as a source of vitamin D is more important than dietary intake, even in winter.
In oily fish is also vitamin D. Excess of vitamin D is broken down by the body.

The UV index must be strong enough to make vitamin D3 in the skin. With a UV index 3, when your shadow is shorter than your height, the sun is high enough. That is in our region in March to November, between twelve and three hours. Beyond the sun is therefore too low.
Behind glass (car, inside ..) the sun cannot make vitamin D3 in your skin.
It can in the shade under a tree, but then it will take twice as long.
In summer, daily exposures of 15 to 30 minutes around noon, to head, hands and forearms would be for people with fair skin sufficient to make the necessary amount of vitamin D. If more skin is exposed, a shorter time is sufficient.

The UV index is a measure of the amount of UV radiation that varies in the Netherlands between 0 and 7. The higher the sun, the stronger the UV index is. In the summer, when the sun is high, between twelve and three o'clock in the afternoon, the power is 6-7. In winter, when the sun is low, it is often less than 1. Closer to the equator, the UV radiation is stronger and seasonal variations are smaller.

‘An apple a day keep the doctor away. Especially if you aim well.’(Winston Churchill)
Englishmen are not brown by the sun, they rust.