Vitamins, minerals and amino acids
Vitamine B3
The amount of vitamin B3 in the blood; a deficiency is very rare in the Netherlands, and too much can result from supplements.
Everything about this testWhat it measures
Vitamin B3 (niacin) is a collective name for nicotinic acid and nicotinamide. The body turns them into the helper substances NAD and NADP, which are needed to convert proteins, fats and carbohydrates into energy. Niacin is found in protein-rich foods such as chicken, fish, dairy products and eggs, and in whole-grain products; the body can also make it itself from the amino acid tryptophan. Which form the test measures differs per laboratory.
- Rarely: vitamin B3 deficiency (pellagra) with severe malnutrition or a severe disorder of the stomach and gut
- Too much vitamin B3 from high-dose supplements
High
A raised vitamin B3 is caused by supplements; you cannot get too much from a normal diet. High doses of nicotinic acid widen the blood vessels, which can cause flushing. A very large amount of nicotinamide can damage the liver and the eyes, and an excess can also cause nausea, pain and bowel symptoms. According to the Dutch Society for Clinical Chemistry (NVKC), true poisoning is rare.
Low
A low vitamin B3 may fit a deficiency, but a deficiency is very rare in the Netherlands because a normal diet contains more than enough niacin. A deficiency occurs mainly with severe malnutrition, a very one-sided diet based on maize or a severe disorder of the stomach and gut, often together with other vitamin deficiencies. A severe deficiency (pellagra) causes skin changes, especially in combination with sunlight, diarrhea, and symptoms that resemble dementia. A slightly low value without these symptoms says little.
If your result is abnormal
With a low value and matching symptoms, the GP looks for malnutrition or a bowel disease and also looks at other nutritional deficiencies. With a raised value due to supplements, the advice is usually to stop taking them, and if there are symptoms the GP may check the liver values.
Reliability
According to the Dutch Society for Clinical Chemistry (NVKC), the test is used in the rare case of a suspected severe deficiency or an excess. Laboratories measure different forms of vitamin B3 with their own reference values, which makes results hard to compare. Without matching symptoms, a single value has little meaning.
Limitations
- Supplements and multivitamins raise the value.
- The form measured (for example nicotinamide or NAD), the measurement method and the reference values differ per laboratory.
- A deficiency usually occurs together with other nutritional deficiencies; a single B3 value does not give a complete picture of this.
How common is this
According to the Netherlands Nutrition Centre (Voedingscentrum), a vitamin B3 deficiency is extremely rare in the Netherlands, because our food contains more than enough niacin. Pellagra occurs mainly in parts of the world where maize is the staple food. Too much vitamin B3 only occurs with the use of high-dose supplements.
Who is this useful for
Only useful when there is a concrete suspicion of a severe deficiency, such as with severe malnutrition or a severe bowel disease with skin changes, diarrhea and confusion, or with symptoms while taking high-dose B3 supplements. In healthy people without symptoms the result says little; with a normal Dutch diet a deficiency is virtually ruled out.
Downsides and risks
- Because a deficiency is so rare, a slightly low result in someone without symptoms can lead to unnecessary worry or unnecessary further testing.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results