"...all doctors should be able to diagnose and treat nutritional deficiencies."

Royal College of Physicians. Nutrition and Patients: A Doctor's Responsibility. London 2002

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Vitamins

Main page | Energy & Protein | Vitamins | Minerals | Essential Fatty Acids

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Vitamin A

Vitamin A is provided in two forms as retinol – animal-derived, pre-formed vitamin A, and as beta-carotene – vegetable-derived vitamin A which needs to be converted into retinol.  By standard convention in the UK 6 parts of beta-carotene are needed to produce one part of retinol.  The food content of retinol is then expressed as Retinol Equivalents, REs, made up of the total of retinol plus one sixth of the dietary content of beta-carotene.
However in the United States the calculation of retinol from beta-carotene is one sixth that from supplements but only one twelfth that from food sources and their terminology is Retinol Activity Equivalents, RAEs, rather than REs.  In the US the retinol content of liver and cheese is considerably lower than that in the UK and the data is included for comparison.  The contents of retinol for full-fat milk and cream in the UK and US are however very similar.

In the UK as well as many countries around the world margarine is, by law, fortified with retinol to the level found in butter during the summer months.  The average UK diet provides approximately two thirds of vitamin A as retinol and one third as beta-carotene. Additionally there appears to be considerable individual variation in the efficiency of conversion of beta-carotene to retinol, with males being more efficient than women.

Adult Requirements and Intakes

 
Men
Women
Estimated Average Requirements ug/day
500
400
Mean Intakes ug/day – NDNS data
1017
800

Average Percentage of Intake Provided by Nutritional Supplements

Pre-formed Retinol

 
Infants
1.5 to 4.5 yrs
Children
4 to 18 yrs
Adults
19 to 64 yrs
Elderly –
Free-living
> 65 yrs
Elderly –
Institutional
> 65 yrs
Males
14%
11%
15%
10%
1%
Females
19%
10%
12%
13%
2%

Beta-Carotene

  Infants
1.5 to 4.5 yrs
Children
4 to 18 yrs
Adults
19 to 64 yrs
Elderly –
Free-living
> 65 yrs
Elderly –
Institutional
> 65 yrs
Males 0 0 1% Negligible Negligible
Females 0 0 3% Negligible Negligible

Content of Individual Foods - Retinol

Food Content of Retinol (Retinol Equivalents) ug per 100g
Lambs liver, fried 19710
Lambs liver, fried (USDA)^ 7782 (RAE)
Chicken liver, fried 10500
Chicken liver, fried (USDA)^ 4296 (RAE)
Butter 1059
Butter, salted (USDA)^ 684 (RAE)
Margarine, soft, polyunsaturated* 733
Cream, double 859
Cheddar Cheese 387
Cheddar Cheese (USDA)^ 265 (RAE)
Cream Cheese 421
Cottage Cheese 48
Eggs, hens’, boiled 190
Eggs, hens’, boiled (USDA)^ 169 (RAE)
Whole milk, average 36
Semi-skimmed milk, average 20
Skimmed milk 1

* Fortified food
^ United States Department of Agriculture National Nutrient Database, Standard Release 20.
www.ars.usda.gov/Aboutus/docs.htm?docid=6300

RAE, Retinol Activity Equivalents, the US measure of retinol activity

Content of Individual Foods – Beta-Carotene

Food
Content of Carotene
ug per 100g
Retinol Equivalents
ug per 100 g
Paprika
36250
6040
Chilli powder
21000
3500
Mixed herbs, dried
8103
1350
Carrots, old, boiled
13402
2233
Carrots, young, raw
7807
1301
Spinach, boiled
6604
1100
Sweet potato, yellow flesh, boiled
3960
660
Peppers, capsicum, red, raw
3840
640
Cabbage, average, boiled
805
134
Mango, ripe, raw
696
116
Tomatoes, raw
564
94
Peas, frozen, boiled
405
67
Plums, average, raw
376
62

 

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Vitamin D

The two main forms of vitamin D are ergocalciferol (vitamin D2), which is derived from plant sources and cholecalciferol (vitamin D3), which is derived from animal sources by the action of sunlight on the skin.  Dietary vitamin D, which is mainly of animal origin, only provides 10% of our requirement with the remainder coming from sunlight exposure.  As the rate of production declines in the elderly and is less in those of non-European origins with darkened skin and in anyone with poor sun exposure the dietary intakes become particularly important.  It is, however, difficult for the whole requirement to be fulfilled adequately by diet alone.

Adult Requirements and Intakes

 
Men
Women
Estimated Average Requirements ug/day
None*
None*
Mean Intakes ug/day – NDNS data
4.2
3.7

*None – if adequate sunlight exposure

10 ug/day for those:

  • aged 65 years or more
  • inadequate sun exposure
  • pregnant or lactating women

Average Percentage of (Dietary) Intake Provided by Nutritional Supplements

 
Infants
1.5 to 4.5 yrs
Children
4 to 18 yrs
Adults
19 to 64 yrs
Elderly –
Free-living
> 65 yrs
Elderly –
Institutional
> 65 yrs
Males
28%
7%
12%
11%
1%
Females
40%
5%
30%
15%
2%

Content of Individual Foods

Food Vitamin D content (ug) per 100g
Cod liver oil 210
Grilled herring 16.1
Trout, rainbow, grilled 9.6**
Tinned salmon 9.2
Grilled mackerel 8.8
Special K Cereal 8.3
Margarine, soft polyunsaturated* 7.9
Salmon, grilled 7.1
Tinned sardines 5.0
Bran flakes (fortified) 4.2
Ricicles* 4.2
Eggs – hen’s, boiled 1.8
Pork loin chops, roasted, lean and fat 1.1
Pork loin chops, grilled, lean 0.8
Bacon, streaky, grilled 0.7
Butter 0.9
Lamb’s liver, fried 0.9
Beef rump steak, grilled 0.4
Cheddar Cheese 0.3
Corn Flakes 0

*Fortified food
**The skin of rainbow trout contains 24ug vitamin D per 100g

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Vitamin E

This vitamin is present in foods as two series of compounds, four tocopherols and four tocotrienols, each having a different level of vitamin E activity.  The main food sources are nuts and seeds and oils derived from them.  Though the content of vitamin E is quite stable at room temperature, when heated in air the vitamin E soon oxidises and its chemical activity is lost.
Vitamin E activity is expressed as α-tocopherol equivalents, which is the sum of α-tocopherol, 40% of the β-tocopherol, 10% of the γ-tocopherol, 1% of the δ-tocopherol, 30% of α-tocotrienol, 5% of the β-tocotrienol, 1% of the γ-tocotrienol and 1% of δ-tocotrienol.

Adult Requirements and Intakes

 
Men
Women
Estimated Average Requirements ug/day
None set
None set
Mean Intakes ug/day – NDNS data
13.4
15.0

Average Percentage of Intake Provided by Nutritional Supplements

 
Infants
1.5 to 4.5 yrs
Children
4 to 18 yrs
Adults
19 to 64 yrs
Elderly –
Free-living
> 65 yrs
Elderly –
Institutional
> 65 yrs
Males
2%
0
21%
11%
0
Females
2%
6%
46%
35%
0

 

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Vitamin K

Vitamin K is derived from two sources, phylloquinone, which is derived from plant sources and menaquinones, which are synthesised by bacteria resident in the bowel.  Adults can become deficient as a result of a poor diet or Persistent use of antibiotics.

Adult Requirements and Intakes

 
Men
Women
Estimated Average Requirements ug/day
None set
None set
Mean Intakes ug/day – NDNS data
Data not presented
Data not presented

Requirements are considered to normally be in the range of 0.5 and 1.0 ug/kg body weight/day.

Average Percentage of Intake Provided by Nutritional Supplements
Not assessed

Content of Individual Foods

Food Vitamin K (ug) per 100g
Spinach, boiled 575
Fresh parsley 548
Spring greens, boiled 393
Watercress, raw 315
Savoy cabbage, boiled 201
Broccoli, boiled 135
Brussels sprouts, boiled 127
Rapeseed oil 112.5
Olive oil 57.5
Asparagus, boiled 51.82

 

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Vitamin B1 (Thiamin)

The requirement for vitamin B1, thiamin, is dependent upon total energy intake due to its importance in the metabolism of carbohydrates, fats and alcohol.  Thiamin is very water soluble and is easily lost in the preparing and cooking of food.  Processed foods contain much less than their initial ingredients and some such as white flour, white bread, and some breakfast cereals are fortified with this vitamin as well as other nutrients. 

Adult Requirements and Intakes

 
Men
Women
Estimated Average Requirements mg/day
0.77
0.57
Mean Intakes mg/day – NDNS data
2.22
1.94

Based upon an energy EAR of 1900 kcl/day for women and 2,550 kcl/day for men.

Average Percentage of Intake Provided by Nutritional Supplements

 
Infants
1.5 to 4.5 yrs
Children
4 to 18 yrs
Adults
19 to 64 yrs
Elderly –
Free-living
> 65 yrs
Elderly –
Institutional
> 65 yrs
Males
0
<1%
10%
4%
1%
Females
0
2%
21%
30%
2%

Content of Individual Foods

Food Thiamin content (mg) per 100g
Yeast extract 4.1
Sunflower seeds 1.6
Pork steaks 1.45
Lamb chops 0.17
Venison 0.16
Chicken breast 0.14
Beef steak 0.13
Weetabix 1.20
Cornflakes* 1.20
Brazil nuts 0.67
Chicken liver 0.63
Baked potatoes 0.37
Plaice 0.29
Salmon 0.25
Wholemeal bread 0.25
White bread* 0.24
Onion, fried in corn oil 0.08
Fruit cake 0.08

* Fortified food

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Vitamin B2 (Riboflavin)

Riboflavin together with thiamin and vitamin B3 plays an important role in energy production.  It is less water-soluble than thiamin and thus less is lost in food preparation and cooking.  However, it is easily destroyed by bright sunlight.  Riboflavin has a bright yellow/green colour which is evident in the urine after high-dose supplements are taken.

Adult Requirements and Intakes

 
Men
Women
Estimated Average Requirements mg/day
1.0
0.9
Mean Intakes mg/day – NDNS data
2.33
2.02

Average Percentage of Intake Provided by Nutritional Supplements

 
Infants
1.5 to 4.5 yrs
Children
4 to 18 yrs
Adults
19 to 64 yrs
Elderly –
Free-living
> 65 yrs
Elderly –
Institutional
> 65 yrs
Males
0
1%
9.5%
0
0
Females
10%
3%
21%
0
0

Content of Individual Foods

Food Riboflavin content (mg) per 100g
Yeast extract 11.9
Calves liver 2.89
Cornflakes (fortified) 1.3
Crab, boiled 0.86
Almonds 0.75
Roast venison 0.69
Roast duck 0.51
Muesli no added sugar 0.4
Cheddar cheese 0.39
Eggs 0.35
Mushrooms 0.31
Semi-skimmed milk 0.24

 

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Vitamin B3 (Niacin)

Vitamin B3 exists in two forms as niacin (nicotinic acid) and as nicotinamide.  They can be obtained preformed from the diet but approximately half of our requirement is fulfilled from the conversion from the amino acid tryptophan by a vitamin B6 dependent enzyme.  The total intake is expressed as niacin equivalents, defined as total niacin intake plus one sixtieth of the tryptophan content of the diet.
The requirement for vitamin B3 is dependent upon energy intake.

Adult Requirements and Intakes

 
Men
Women
Estimated Average Requirements mg/day
14.0
10.5
Mean Intakes mg/day – NDNS data
46.4
32.8

 Based upon an energy EAR of 1900 kcl/day for women and 2,550 kcl/day for men

 

Average Percentage of Intake Provided by Nutritional Supplements

 
Infants
1.5 to 4.5 yrs
Children
4 to 18 yrs
Adults
19 to 64 yrs
Elderly –
Free-living
> 65 yrs
Elderly –
Institutional
> 65 yrs
Males
1%
1%
3.5%
2%
0
Females
2%
2%
6.0%
5%
1%

Content of Individual Foods

Foods Niacin content as niacin equivalents mg per 100g
Yeast extract 73
Grilled chicken breast 22
Tinned tuna in oil 21.2
Calves liver fried 19.4
Peanuts 19.3
Weetabix 17.5
Cornflakes* 15.9
Pork steaks 15.7
Smoked salmon 13.5
Grilled mackerel 13.3
Cheddar cheese 6.9
Muesli no added sugar 6.8
Wholemeal bread 6.1
White bread* 3.6
Frozen peas 2.5
Lager 1.0
Beer 0.4
Tea 0.4

*Fortified food

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Vitamin B5 (Pantothenic acid)

Pantothenic acid is widely distributed in foods and thus intakes are almost always satisfactory.  It plays a central role in the release of energy from all sources.  Because deficiency is rare and difficult to induce it has been difficult to precisely identify requirements. 

Adult Requirements and Intakes

 
Men
Women
Estimated Average Requirements mg/day
None set
None set
Mean Intakes mg/day – NDNS data
7.8
6.4

Average Percentage of Intake Provided by Nutritional Supplements

 
Infants
1.5 to 4.5 yrs
Children
4 to 18 yrs
Adults
19 to 64 yrs
Elderly –
Free-living
> 65 yrs
Elderly –
Institutional
> 65 yrs
Males
3%
0
8%
2%
0
Females
0
2%
15%
11%
0

Content of Individual Foods

Foods Pantothenic acid (mg) per 100g
Chicken liver 5.90
Broad beans, boiled 3.80
Peanuts 2.66
Roast duck 2.60
Pork steaks 2.09
Mushrooms 2.00
Chicken breast 1.67
Rainbow trout 1.58
Lamb chops, lean 1.4
Eggs 1.3

 

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Vitamin B6

The term vitamin B6 includes pyridoxal, pyridoxamine and pyridoxine and their 5’-phosphate forms which are interconvertible.  Requirement is related to protein intake due to its relation to amino acid metabolism.  It is heat sensitive and deficiency has resulted in infants from the severe over-heating of formula milk.

Adult Requirements and Intakes

 
Men
Women
Estimated Average Requirements mg/day
0.7
0.59
Mean Intakes mg/day – NDNS data
3.3
2.9

Based upon a protein intake of 55 g/day for men and 45 g/day for women.

Average Percentage of Intake Provided by Nutritional Supplements

 
Infants
1.5 to 4.5 yrs
Children
4 to 18 yrs
Adults
19 to 64 yrs
Elderly –
Free-living
> 65 yrs
Elderly –
Institutional
> 65 yrs
Males
0
0
12%
5%
0
Females
0
10%
31%
20%
0



Content of Individual Foods

Food Vitamin B6 content (mg) per 100g
Bran flakes (fortified) 2.3
Yeast extract 1.6
Avocado 1.1
Calves liver 0.89
Grilled salmon 0.81
Pork steaks 0.68
Walnuts 0.67
Lean rump steak 0.65
Chicken breast 0.63
Baked potato 0.54
Tinned tuna in oil 0.51
Red peppers raw 0.36
Banana 0.29
Wholemeal bread 0.11
White bread 0.08

 

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Folate

Folate is the form of this vitamin found in foods, especially green leafy vegetables (foliage), and folic acid is the simpler chemical form that is used as a supplement or added to foods.  Folate is needed for rapidly dividing cells hence deficiency can affect the health of a pregnancy, the bone marrow and anaemia and the lining of the gastrointestinal tract.  At present consideration is being given to fortifying flour and perhaps other foods in the UK as has happened in the United States, in order to reduce the risk of pregnancies being affected by neural tube defects (spina bifida). 

Adult Requirements and Intakes

Men
Women
Estimated Average Requirements ug/day 150 150
Mean Intakes ug/day – NDNS data 359 292

Average Percentage of Intake Provided by Nutritional Supplements

  Infants
1.5 to 4.5 yrs
Children
4 to 18 yrs
Adults
19 to 64 yrs
Elderly –
Free-living
> 65 yrs
Elderly –
Institutional
> 65 yrs
Males 1% <1% 4.0% 3% 0
Females 1% 2% 14% 6% 1%

Content of Individual Foods

Food Folate content (ug) per 100g
Yeast extract 2620
Chicken liver 1350
Flora margarine* 500
Butter 0
Cornflakes* 333
Blackeye beans,boiled 210
Asparagus, boiled 173
Raw spinach 114
Brussels sprouts, boiled 110
Beetroot, boiled         110
Frozen peas 47
Baked potatoes 44
Wholemeal bread 40
White bread               25
Cabbage, boiled 39
Beer 5
White pasta 7
White rice 7

* Fortified food

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Vitamin B12

This vitamin is only found in animal-based foods and the body normally has a store in the liver which can last up to four years.  Unlike the other B vitamins it is relatively stable during cooking.  Deficiency can result from consuming an inadequate vegan or poor quality vegetarian diet but is also not uncommon in the elderly due to absorption difficulties.  For this reason in the US those aged over 50 years are advised to eat foods fortified with vitamin B12 or to take a supplement.   

Adult Requirements and Intakes

 
Men
Women
Estimated Average Requirements ug/day
1.25
1.25
Mean Intakes ug/day – NDNS data
7.6
5.1

Average Percentage of Intake Provided by Nutritional Supplements

 
Infants
1.5 to 4.5 yrs
Children
4 to 18 yrs
Adults
19 to 64 yrs
Elderly –
Free-living
> 65 yrs
Elderly –
Institutional
> 65 yrs
Males
3%
0
4.5%
0
0
Females
0
0
6.5%
2%
0

Content of Individual Foods

Food Cobalamin content (ug) per 100g
Calves liver 58
Cockles 47
Mussels 22
Tinned sardines 15
Tinned tuna in oil 5
Lean rump steak 3
Cheddar cheese 2.4
Baked cod 2
Eggs 1.1
Whole milk 0.9
Butter 0.3
Margarine 0
Flora margarine* 2.5
Flora Light margarine  
Marmite 1

* Fortified food

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Biotin

This B vitamin is required for fat metabolism and deficiency is rare but can occur as a result of consuming raw eggs.  The whites contain a protein, avidin, which binds with biotin making it unavailable for absorption.  Paradoxically a good source is egg yolk, as is meat and offal. 

Adult Requirements and Intakes

 
Men
Women
Estimated Average Requirements ug/day
None set
None set
Mean Intakes ug/day – NDNS data
44
33

Average Percentage of Intake Provided by Nutritional Supplements

  Infants
1.5 to 4.5 yrs
Children
4 to 18 yrs
Adults
19 to 64 yrs
Elderly –
Free-living
> 65 yrs
Elderly –
Institutional
> 65 yrs
Males
0
0
7%
0
3%
Females
0
0
13%
4%
4%

 

Content of Individual Foods

Food Biotin content (ug) per 100g
Chicken liver 216
Hazelnuts 76
Peanuts 72
Plaice 48
Soya beans, boiled 25
Oatcakes 17
Eggs 16
Mushrooms 12
Tinned sardines in brine 10
Mussels 9
Blackeye beans, boiled 7

 

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Vitamin C (Ascorbic acid)

Vitamin C has played a central role in the understanding of essential micronutrients as deficiency causes scurvy, which has been known since historic times and developed in seafarers due to their reduced intake of fruit and vegetables.  Vitamin C is added to foods as a natural preservative as it helps to reduce food spoilage from oxidation due to exposure to the air.  The low content of vitamin C in some apples results in them browning quickly when cut.

 

Adult Requirements and Intakes

 
Men
Women
Estimated Average Requirements mg/day
25
25
Mean Intakes mg/day – NDNS data
101.4
112

Average Percentage of Intake Provided by Nutritional Supplements

 
Infants
1.5 to 4.5 yrs
Children
4 to 18 yrs
Adults
19 to 64 yrs
Elderly –
Free-living
> 65 yrs
Elderly –
Institutional
> 65 yrs
Males
5%
5%
18%
6%
5%
Females
7%
9%
25%
11%
13%

Content of Individual Foods

Food Vitamin C Content (mg) per 100g
Blackcurrants 200
Red peppers, raw 140
Green peppers, raw 120
Strawberries 77
Watercress 62
Brussels sprouts, boiled 60
Kiwi 59
Oranges 54
Broccoli, boiled 44
Orange juice 39
Cabbage, boiled 20
Tomatoes 17
Baked potato 14
Frozen peas 12
Stewed apple 11
Eating apple 6
Plums – eating 4

 

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Main page | Energy & Protein | Vitamins | Minerals | Essential Fatty Acids

 



Copyright Dr. Alan Stewart M.B.B.S.M.R.C.P. (UK)M.F. Hom.
47 Priory Street, Lewes, East Sussex. BN7 1HJ
Tel 01273 487003 Fax: 01273 487576