Vitamins are involved in numerous processes throughout our bodies. For example, they take part in the production of hormones, enzymes and blood cells. In addition, our skin, muscles, nerves and immune systems all depend upon vitamins. Even a slight vitamin deficiency can become noticeable: we tire more easily, have trouble concentrating and are more susceptible to colds. Since our bodies cannot produce most vitamins on their own we have to ingest them as part of our diet.
Two groups of vitamins
Some vitamins are fat-soluble (A, D, E and K), while others are water-soluble. Our bodies can only utilise fat-soluble vitamins if we ingest them in combination with dietary fat. For example, when you are preparing carrots, you should include so me fat, or eat them along with a buttered slice of bread.
The best-known water-soluble vitamin is Vitamin C, but in addition, there is the large group of B-vitamins, including B1, B2, B6, B12, niacin, biotin, pantothenic acid and folic acid. Vitamins should be part of your daily diet to assure an adequate supply.
All but two of them cannot be produced by our bodies, so they must be provided through our daily diet. Exceptions are vitamin D, which can be obtained from sunlight on skin, and niacin (B vitamin), small amounts of which can be made from an amino acid (tryptophan).
A word of warning however: just as our bodies do not function well with a lack of vitamins, excessive amounts of vitamins, especially of fat-soluble vitamins, are also unhealthy in the long term.
A plentiful supply with a varied diet
A balanced meal plan will provide us with sufficient amounts of vitamins. The following table will give you an overview of the functions of the various vitamins and their presence in different foods.
Vitamin A and beta-carotene (that the body converts into Vitamin A)
Vision, skin, growth
As retinol(vitamin A) in foods from animal sources, eg liver,
whole milk, butter, cheese, fish (eg salmon).
As carotenoids(ß-carotene is the most common) in foods from plants, eg carrots, tomatoes, dark green leafy vegetables (eg spinach), sweet potatoes, mangoes.
Bones, teeth, calcium absorption
Fatty fish (eg salmon, tuna), egg yolks, liver.
Foods fortified with vitamin D such as margarine, milk, yogurt,breakfast cereals
Protecting body cells
Plant oils, such as canola, sunflower or soybean oil. Nuts like almonds, peanuts, sunflower seeds. Leafy green vegetables (eg spinach, mustard greens), eggs
Blood clotting, bones
Green leafy vegetables, eg cabbage, spinach, broccoli. Fruits, eg kiwis, apricots. Eggs, dairy products
B-Vitamins (B1, B2, B6, B12)
Obtaining energy from protein, fat, carbohydrates, nerve function, blood formation
Wholegrain products, pulses, pork, milk, vegetables, fruit, fish
Formation of blood and body cells, nervous system development in the unborn baby
Green leafy vegetables (eg turnip greens, spinach, butter, lettuce), broccoli, asparagus, corn, tomatoes, fruits (eg oranges), lentils, kidney, navy, soybeans, green peas. Liver, whole grain, sunflower seeds, peanuts. Most enriched grain products.
Iron absorption, nervous system, blood vessels, connective tissue
Citrus fruits, berries (eg cranberries, blueberries, raspberries, strawberries), melons, green and red peppers, tomatoes, potatoes, broccoli
Bioavailability (sometimes mistakenly called absorption rate) is a general term that refers to how well a nutrient (eg vitamins) can be absorbed and used by the body. It is affected by the following:
Vitamins need to be treated with care
Prolonged storage and boiling in lots of water at excessive temperatures – these are things that vitamins really don’t like at all. If you want to enjoy fruit and vegetables along with all of their important nutrients, ensure you treat them gently.
Tips for preparation with vitamin rich fruits and vegetables:
Enhancing quality of life and contributing to a healthier future