Vitamins – Keeping Us Fit In Every Situation

Vitamins–Keeping Us Fit In Every Situation

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

Important for…

Good Sources

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.

 

 

 

Vitamin D

Bones, teeth, calcium absorption

Fatty fish (eg salmon, tuna), egg yolks, liver.
Foods fortified with vitamin D such as margarine, milk, yogurt,breakfast cereals

Vitamin E

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

Vitamin K

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

Folic acid

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.

 

Vitamin C

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:

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:

  • The composition of individual foods, eg vitamin C increase the bioavailability of iron from non-haem sources such as plants (vegetable sources), eg spinach

  • Diet as a whole, eg dietary fat is necessary for the absorption of fat-soluble vitamins

  • Conditions in the body; some vitamins require specific substances (molecules) in order to be absorbed, or specific transport systems in the blood to travel to the tissue where they are needed. For example, vitamin B12(eg from meat) must be bound to a protein (intrinsic factor) produced in the stomach before it can be absorbed in the intestine. If this protein is not available, adequate amounts of vitamin B12cannot be absorbed

 

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:

  • Serve fruits and vegetables raw whenever possible

  • Wash vegetables (and fruits) under running water whole and before peeling

  • Cutting vegetables into large pieces prevents vitamin loss

  • Cover fruits and vegetables immediately after cutting to prevent vitamin loss through light and air

  • The best cooking methods for vegetables are steaming,stewing/braising and pressure cooking

  • Use the cooking liquid whenever possible

  • Cook for the shortest possible time

  • Cook until just tender, not mushy

  • Cooked vegetables should be quickly heated to 70° C (158° F) to destroy enzymes which threaten the vitamins

  • The quick defrosting of fruits and vegetables decreases vitamin loss

  • Serve immediately. Keeping food warm causes a vitamin C loss of 4 – 17% within one hour and 7 – 34% within two hours

  • If you use frozen vegetables:

    • Don’t thaw them before cooking

    • Heat the water first, then add the vegetables

    • If you use them for cold dishes, cook them thoroughly beforehand

    • Use the microwave for heating them

  • If you use canned vegetables:

    • Use the juice to cook the vegetables in

    • Never boil canned vegetables

    • Use the microwave for heating them

    • Avoid excessive stirring while warming them up