Vitamin B3 (Niacin)
What is Vitamin B3 (Niacin)?
Niacin is a water-soluble vitamin and known as vitamin B3. Niacin is involved in more than 400 reactions in the human body, and is important for the metabolism, nervous system, and antioxidant protection. The research is slim on autism and niacin, though individuals with autism who are picky eaters may be at higher likelihood for deficiency.
Niacin is the commonly used name for nicotinic acid, nicotinamide, and others. Tryptophan, an amino acid, can be converted to niacin in the body, which is why it is considered a source of niacin in the diet. [1]
Niacin is very important for metabolism, proper nervous system function, and antioxidant protection. [6]
Niacin is very easily absorbed, even at high levels. Ingested niacin is primarily absorbed in the small intestine, but some is absorbed in the stomach. The body can store small amounts in the red blood cells, but, since it is water-soluble, anything that is not stored will be excreted in the urine.
Some research shows that niacin supplementation can be helpful for children with autism, but more research needs to be done.
Sources of Niacin
Niacin is present in a wide variety of foods, like meat products that provide high bioavailability forms of niacin (NAD and NADP). Plant-based foods provide niacin in the form of nicotinic acid. Some food in the United States like breakfast cereals are fortified with added niacin to increase national intake.
Liver
Pork
Fish (ex: tuna, salmon, anchovies
Certain vegetables like mushrooms, green peas, and potatoes
Foods such as pastas, grains, and breads may be enriched with niacin. Those who are sensitive to fortified B vitamins or have methylation issues should avoid such grains and consume natural sources instead (listed above).
Recommended Intake
These recommendations are based on the Recommended Dietary Allowance (RDA), which is the average daily level of intake sufficient to meet the nutrient recommendations of nearly all (97-98%) of healthy individuals.
Males
o-6 months: 2 mg/d
7-12 months: 4 mg/d
1-3 years: 6 mg/d
4-8 years: 8 mg/d
9-13 years: 12 mg/d
14-18 years: 16 mg/d
19-50 years: 16 mg/d
51+ years: 16 mg/d
Females
o-6 months: 2 mg/d
7-12 months: 4 mg/d
1-3 years: 6 mg/d
4-8 years: 8 mg/d
9-13 years: 12 mg/d
14-18 years: 14 mg/d
19-50 years: 14 mg/d
Pregnancy: 18 mg/d
51+ years: 14 mg/d
Deficiency
Severe niacin deficiency will cause a condition called pellagra where the skin will turn brown in pigment or rash and become rough when exposed to sunlight. Pellagra can also cause other symptoms including:
Bright red tongue
GI issues like vomiting, constipation or diarrhea
Depression
Headache
Fatigue
Memory loss
Aggression
Paranoid behavior
Suicidal behaviors
Hallucinations
Anorexia
While pellagra is rare in developed countries, it still happens for some who live in poverty and are unable to meet dietary needs for niacin. Treatment for pellagra is supplementation to treat the deficiency.
Individuals at increased risk of niacin deficiency includes:
Individuals with restrictive diets
Vegetarians/vegans
Individuals with undernutrition
Inadequate B2/B6/iron intakes
Hartnup disease
Carcinoid syndrome
Toxicity
There have not been any negative effects from consuming niacin within foods. However, high niacin intake through supplements or nicotinic acid and nicotinamide can cause toxicity. Side effects include flushing of the arms, face, and chest along with a burning and itchy sensation, or nausea. This can last around 30 minutes after taking the supplement and will continue to happen each time the excessive dose is taken. Typically this is more of an unpleasant side effect, but it can be paired with headaches, rashes, dizziness and/or decreased blood pressure. Side effects can be reduced by taking the supplement along with foods.
The upper limit for niacin intake is related to supplementation usage, not intake from foods.
Males & Females
o-12 months: Not determined
1-3 years: 10 mg/d
4-8 years: 15 mg/d
9-13 years: 20 mg/d
14-18 years: 30 mg/d
19-50 years: 35 mg/d
51+ years: 35 mg/d
Supplements
Niacin is included in multivitamins, B-complex vitamins and by itself as a supplement. Nicotinic acid and nicotinamide are the most commonly found forms of niacin within supplements. Some supplements provide 500 mg or more, which greatly exceeds the recommended daily amount.
Consuming a high amount of supplemental niacin rapidly can lead to skin flushing, so some supplements advertise an extended or time-released product to reduce these side effects. Niacin can be found in Niaspan and Niacin ER as prescription medications that is used to treat high cholesterol.
Examples
Note: All supplements are linked to Amazon for convenience, however, buying supplements on Amazon does not guarantee quality, as there are many “unverified resellers” selling nutrition supplements. To buy supplements that are verified to be sent directly to the consumer, you can create an account on the Autism Dietitian FullScript and search for the respective supplement under “Catalog”.
DISCLAIMER: Before starting any supplement or medication, always consult with your healthcare provider to ensure it is a good fit for your child. Dosage can vary based on age, weight, gender, and current diet.
Niacin & Autism in the Research
Niacin Supplementation
Some research will show no significant difference in nutritional lab values of niacin after supplementation [2], while others will show that it helped improve the nutritional and metabolic markers of individuals with autism [3] More research needs to be done in this area.
Supplementation of B-vitamins like niacin paired with magnesium can help tryptophan levels in individuals with autism [4].
Niacin Deficiency
There are noted differences in nutritional lab values, like B3, in children with autism when compared to neurotypical children [5].
-
[1] Meyer-ficca M, Kirkland JB. Niacin. Adv Nutr. 2016;7(3):556-8.
[2] Adams JB, Audhya T, Geis E, et al. Comprehensive Nutritional and Dietary Intervention for Autism Spectrum Disorder-A Randomized, Controlled 12-Month Trial. Nutrients. 2018;10(3)
[3] Adams JB, Audhya T, Mcdonough-means S, et al. Effect of a vitamin/mineral supplement on children and adults with autism. BMC Pediatr. 2011;11:111.
[4] Kałużna-czaplińska J, Jóźwik-pruska J, Chirumbolo S, Bjørklund G. Tryptophan status in autism spectrum disorder and the influence of supplementation on its level. Metab Brain Dis. 2017;32(5):1585-1593.
[5] Adams JB, Audhya T, Mcdonough-means S, et al. Nutritional and metabolic status of children with autism vs. neurotypical children, and the association with autism severity. Nutr Metab (Lond). 2011;8(1):34.
[6] Kraemer K, Semba RD, Eggersdorfer M, Schaumberg DA. Introduction: the diverse and essential biological functions of vitamins. Ann Nutr Metab. 2012;61(3):185-91. doi: 10.1159/000343103. Epub 2012 Nov 26. PMID: 23183287.
Authors
April Allen, RDN
Elisa Rocks, RDN
Brittyn Coleman, MS, RDN/LD, CLT
