Niacin

B3 - Niacin

Nicotinic Acid

Nicotinic acid, sometimes called niacin or vitamin B3, is part of the vitamin B complex and one of the ten members of this group known to be an essential nutrient. Apart from sugars, fats and spirit-based alcoholic drinks, most food provides some nicotinic acid, though the high protein foods are the best source, and fruits contain very little. Your liver can also manufacture nicotinic acid from the amino acid tryptophan which occurs in nearly all proteins. So, if you're not getting enough nicotinic acid or tryptophan from your diet you're likely to develop deficiency symptoms.

The most important function of nicotinic acid is the part it plays in converting the food you eat into energy that the body can use, so the more physically active you are the more nicotinic acid you need. This vitamin is also vital for the continual replacement of skin cells and maintenance of healthy skin, as well as nerve function and good digestion.

Maize is the only cereal that does not contain tryptophan, so the deficiency disease pellagra occurs in populations who depend mainly on maize as their staple food, who consume little or no milk and very little or no animal protein. Though scientists knew about nicotinic acid in 1840, it was 100 years before the link was made between this B vitamin and pellagra.

The name pellagra comes from the Italian 'pella' for skin and 'agra' meaning rough and in this condition after the early symptoms of weight loss, weakness and mental difficulties, the skin becomes itchy and scaly especially on the hands, face and neck. Sores in the mouth and tongue, dementia and problems with the brain and nervous system follow. If the condition is treated before irreversible damage is done to the nervous system, the symptoms improve within a day of taking the first dose of nicotinic acid.

Pellagra is very rare in the UK but deficiency symptoms are common. Factors which reduce the absorption of this vitamin are too much alcohol, long term antibiotic treatment, drugs for the treatment of Parkinson's disease, contraceptive pill, smoking and high levels of physical activity through work or sport. The earliest symptoms of deficiency are a sore red tongue, dry scaly skin, sores in and around the mouth, general fatigue, irritability, diarrhoea and giddiness.

Extra amounts of nicotinic acid may be needed by older people with poor digestion, those on very low calorie diets or with eating disorders, diabetics, pregnant or breastfeeding women, anyone who's had part of their stomach or digestive tract removed and everybody who has raised cholesterol.

There is some evidence that nicotinic acid supplements can help in the treatment of acne rosacea, tinnitus (noises in the ears), chilblains and varicose veins, migraine and depression.

The RDA is 18 mg a day though ideally aim for around 25 mg from food and take 50 mg as a supplement when necessary.

BEST SOURCES

LAMBS LIVER
20.1 mg / 100 g
Percentage of daily requirement: 167% from average 150 g portion
Nicotinic acid score: 10/10

PEANUTS
19.3 mg / 100 g
Percentage of daily requirement: 53% from average 50 g portion
Nicotinic acid score: 5/10

BOILED EGGS
3.8 mg / 100 g
Percentage of daily requirement: 21% from 2 boiled eggs
Nicotinic acid score: 2/10

ROAST CHICKEN
15.3 mg / 100 g
Percentage of daily requirement: 127% from average 150 g portion
Nicotinic acid score: 10/10

WHOLEMEAL BREAD
5.9 mg / 100 g
Percentage of daily requirement: 23% from two average slices
Nicotinic acid score: 2/10

SARDINES
11.3 mg / 100 g
Percentage of daily requirement: 63% from average 100 g portion
Nicotinic acid score: 6/10

SWISS MUESLI WITH MILK
9.8 mg / 100 g
Percentage of daily requirement: 48% from average 75 g muesli, 200 g milk
Nicotinic acid score: 5/10