Fat Soluble Vitamins
Here's some useful information about the fat soluble vitamins A, D, E and K together with the best foods that contain them.
Vitamin A
Vitamin A is also known as retinol, and this form can be obtained preformed from our diet from foods of animal origin. Vitamin A can also be obtained from plant foods after conversion from some carotenoids which can be converted to retinol in the body.
Carotenoids are a large group of pigments found in plants, all of which act as antioxidants and may have some cancer-preventing and heart disease risk-reducing qualities. However, just three carotenoids have vitamin A activity; β-carotene is the most readily converted, and α-carotene and γ-carotene also have some activity.
Vitamin A is required for growth and normal development of tissues; long term deficiency results in death. Retinol is required for light gathering in visual pigments for night vision. Deficiency is not uncommon in humans in regions prone to malnutrition, and initial signs are night-blindness and dry eyes. Even prolonged mild deficiency can lead to permanent eye damage.
Vitamin A intake is measured in retinol equivalents (RE) where 6µg of β-carotene is roughly equivalent to 1µg of retinol. Requirements for adults are 700µg RE per day.
Animal Sources
Preformed vitamin A, i.e. retinol, is obtained from animal foods:
Milk, full-cream (100ml) – 55µg
(Milk, skimmed (100ml) – 1µg)
Cheddar Cheese (40g) – 145µg
Cheese, Edam (40g) – 80µg
Cheese, Feta (40g) – 90µg
Cheese, Red Leicester (40g) – 146µg
Cream (50g) – 168µg
Ice-cream (75g) – 111µg
Yoghurt (150g) – 60µg
Butter (8g) – 71µg
Margarine (8g) – 72µg
Egg, boiled – 114µg
Red salmon (115g) – 104µg
Kidney (75g) – 120µg
Liver (90g) – 18,549µg
Plant Sources
Plant sources contribute over a quarter of vitamin A intake in the West.
Apricot – 85µg
Banana – 27µg
Mango – 370µg
Melon, cantaloupe (½) – 709µg
Nectarine – 85µg
Peach – 91µg
Prunes (40g) – 55µg
Carrots (65g) – 1,300µg
Tomatoes (75g) – 75µg
Tomato juice (200ml) – 166µg
Watercress (15g) – 75µg
Brussel sprouts (115g) – 77µg
Runner beans (105g) – 70µg
Broccoli (95g) – 396µg
Peas (85g) – 38µg
Spinach (130g) – 1,300µg
Sweetcorn (70g) – 25µg
Sweet potatoes (150g) – 1,000µg
Vitamin D
Vitamin D is a fat soluble vitamin which acts like a hormone in the control of blood calcium and phospherous levels and bone mineralisation. The two major forms are vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D3 is available from food, but can also be produced in skin exposed to ultraviolet B radiation from sunlight.
Good vitamin D levels can be acquired from sunlight, by exposing your arms and face to the sun as much as is practically possible during the spring and summer months. However, Vitamin D is also abundant in the Western diet and foods rich in it include:
- Mushrooms (80g) – exposed to UV light for 5 mins after harvesting – 2700IU
- Cod liver oil (1tbsp) -1360IU
- Catfish (80g) – 425IU
- Salmon (100g - cooked) - 360 IU
- Mackerel (100g - cooked) - 345 IU
- Sardines (50g -canned in oil, drained) - 250 IU
- Tuna (60g - canned in oil, drained) - 250 IU
- Eel (100g - cooked) - 200 IU
- Milk (250ml whole/semi-skimmed/skimmed - vit D fortified) - 98 IU
- Fortified rice or soya beverage (250ml) - 80 IU
- Margarine (fortified, 1tbsp) - 60 IU
- Sponge pudding prepared from mix and vit D fortified milk (125ml) - 50 IU
- Fortified orange juice (125ml) - 45 IU
- Ready to eat fortified breakfast cereals (200ml) - 40 IU (varies with brand)
- Egg (1 whole) - 20 IU
- Liver, beef (100g - cooked) - 15 IU
- Swiss cheese (30g) - 12 IU
Vitamin E
Vitamin E's role in humans is as the main fat soluble antioxidant in cells. It has a crucial role in helping to stop cholesterol from sticking to the walls of small arteries; the process by which we get heart disease and strokes.
There are two classes of compounds which act as vitamin E. The first, and by far the more potent, are the tocopherols, principally α-tocopherol (90% of the vitamin E present in human tissue), with the less active tocotrienols also contributing to activity.
A good vitamin E intake is essential with a high intake of both omega-6 and omega-3 polyunsaturated fat. Vitamin E is abundant in the Western diet and foods rich in it include (shown as mg α-tocopherol per serving):
- Wheat germ oil (1 tbsp) - 20.3mg
- Sunflower oil (1 tbsp) - 5.6mg
- Cottonseed oil (1tbsp) – 4.8mg
- Safflower oil (1 tbsp) - 4.6mg
- Canola oil (1tbsp) – 2.4mg
- Peanut oil (1tbsp) – 2.1mg
- Olive oil (1tbsp) – 1.9mg
- Corn oil (1 tbsp) - 1.9mg
- Soybean oil (1 tbsp) - 1.3mg
- Almonds (30g) - 7.5mg
- Sunflower seeds (30g) - 6.0mg
- Hazelnuts (30g) - 4.3mg
- Peanut butter, smooth style, fortified (2 tbsp) - 4.2mg
- Peanuts, dry roasted (30g) - 2.2mg
- Pine nuts (30g) – 2.6mg
- Brazil nuts (30g) – 1.6mg
- Mixed nuts (30g) – 3.1mg
- Broccoli, frozen, boiled (20g) - 1.2mg
- Spinach, raw (20g) - 0.6mg
- Avocado, raw (½ fruit) – 2.1mg
- Kiwi (1 medium) - 1.1mg
- Mango, raw (20g) - 0.9mg
- Tomato purée (60g) – 2.8mg
- Tomato sauce (50g) – 2.5mg
- Carrot juice (200ml) – 2.1mg
- Sardines, canned in oil, drained (90g) – 1.7mg
- Herring (90g) – 1.5mg
- Oats (50g) – 0.7mg
- Fortified breakfast cereals (approx 30g) – 1.6-12.8mg (depending on brand)
Vitamin K
Vitamin K is a fat soluble vitamin which is involved in healthy bone development (a deficiently may lead to bone disease) and in the blood clotting process.
There are three source groups of vitamin K: from animal products in small amounts, from plant sources (phylloquinone - i.e. leafy green vegetables, vegetable oils and some cereal products), and from the bacteria microflora in our digestive system (menaquinones). Because these bacteria synthesise vitamin K within our body there is no recommended minimum intake of vitamin K and clinical deficiency is rare, though is more common in babies. However, diets rich in fatty, sugary and processed foods can compromise our gut flora, as can some additives and pesticides that are often a part of modern food production, as well as antibiotic treatment.
As the majority of vitamin K is obtained from our gut flora, the use of probiotics and prebiotics may help increase production. Probiotics are live strains of 'good' bacteria, obtained from live yoghurts, powders, capsules or specially formulated probiotic drinks. Using probiotics increases the colonies of our gut flora. Prebiotics are certain nutrients and constituents of food which our own gut flora feed on, thus increasing their numbers. Prebiotics include fructo-oligosaccharides (FOS) and some other soluble fibres found in pulses, fruit and some cereal products.
Other than that obtained from bacteria production, the richest food sources of vitamin K include:
- Green leafy vegetables
- Spinach
- Kale
- Brussel sprouts
- Broccoli
- Cabbage
- Cauliflower
- Kelp
- Alfalfa
- Safflower oil
- Blackstrap molasses
- Eggs
- Yogurt
- Swiss chard
- Porridge oats / oatmeal
- Beef liver
- Red meat
- Fish
- Soya oil
- Tomatoes
- Avocados
- Kiwi fruits
- Parsley