Key points
- The NHS names meat, fish, wheat flour and eggs as good sources of niacin, the main name for vitamin B3.
- "Vitamin B3" covers more than one compound: nicotinic acid and nicotinamide, which is also called niacinamide.
- Cells can use these forms, and tryptophan, an amino acid in protein, as starting points for making NAD+.
- That is a description of biology. It is not a claim that eating these foods, or taking any supplement, changes anything for you.
Which foods contain vitamin B3? The NHS lists meat, fish, wheat flour and eggs as good sources of niacin, the usual name for vitamin B3. The link to NAD+ (nicotinamide adenine dinucleotide) is that cells use forms of vitamin B3 as raw material to build NAD+. This guide explains the names, the foods, the routes cells use and where the food facts stop.
Vitamin B3 goes by several names
Vitamin B3 is not one molecule. It is a group name, and the labels, articles and ingredient lists you read may use any of its members.
Niacin, nicotinic acid, nicotinamide and niacinamide
- Niacin is the umbrella name. The NIH Office of Dietary Supplements uses it as the generic name for nicotinic acid, nicotinamide and related compounds. It is also the name used on UK labels and in the UK's list of nutrient reference values.
- Nicotinic acid is one form of niacin.
- Nicotinamide is another form. Niacinamide is simply another name for the same compound, not a different substance.
- Nicotinamide riboside is a related compound that the NIH Office of Dietary Supplements lists among niacin's derivatives. It has its own guide: nicotinamide riboside (NR) and NAD+, explained.
Two names that look alike are worth keeping apart. Nicotinamide is a form of vitamin B3. Nicotinamide adenine dinucleotide, NAD+, is a larger molecule that cells build using nicotinamide as one of its parts.
Foods that contain vitamin B3
| Food named by the NHS | Type of food | Also noted by the NIH Office of Dietary Supplements |
|---|---|---|
| Meat | Animal | Names poultry and beef among animal foods that provide niacin |
| Fish | Animal | Names fish among animal foods that provide niacin |
| Wheat flour | Plant | |
| Eggs | Animal |
Foods that contain protein also provide tryptophan, which the body can use in a similar way, as the next section explains. That is why the UK's Government Dietary Recommendations give niacin figures as "niacin equivalents", which count both.
We have left out amounts per portion on purpose, so that no figure appears here without being checked against its source. If you want to plan your diet around a nutrient, a registered dietitian or your GP is the right person to ask.
How the body uses B3 forms to make NAD+
Cells build NAD+ by more than one route, and each form of vitamin B3 has its own way in.
- From nicotinic acid: a short route of three steps, known to biochemists as the Preiss-Handler pathway.
- From nicotinamide: a recycling route, often called the salvage pathway. When enzymes use up NAD+, nicotinamide is released, and cells can turn it back into NAD+.
A review in Cell Metabolism describes nicotinic acid and nicotinamide, together termed niacin or vitamin B3, as precursors for NAD+. "Precursor" means a molecule that comes earlier in a chain of reactions. It describes a route inside a cell, not an effect on a person.
The tryptophan route
Cells can also make NAD+ from tryptophan, an amino acid found in protein. This route is longer, with eight steps, and is known as the de novo pathway, meaning "from scratch". The NIH Office of Dietary Supplements notes that because the body converts some tryptophan in this way, tryptophan is counted as a dietary source of niacin, and that how much is converted varies considerably between people.
UK dietary figures reflect this. Public Health England's Government Dietary Recommendations define a niacin equivalent as niacin plus tryptophan divided by 60.
Does food contain NAD+ itself?
Many foods do, because foods from plants and animals are made of cells, and NAD+ is found in living cells. A review in Cell Metabolism notes that in animal products, and probably in all uncooked foods, the NAD+ and NADP+ inside the food's cells account for much of their niacin content. The NIH Office of Dietary Supplements also lists NAD and NADP among the forms in which niacin occurs in food.
What happens to NAD+ from food during digestion is a separate question. We make no claim about it, for food or for any supplement.
Why a food fact is not a supplement claim
In Great Britain, a health claim can only be used if it is on the Great Britain nutrition and health claims register. This article makes no health claim for any food, vitamin or supplement. It names foods and describes routes inside cells, and it stops there.
Nothing in this article says that eating these foods, or taking vitamin B3 or NAD+, changes anything for you. If you have a question about your diet or about a supplement, ask a pharmacist, your GP or a registered dietitian.
For how NAD+ works as a molecule once a cell has made it, read NAD+ vs NADH: one molecule, two states. Our Science page covers the basics.
What Pure Limitless sells
Role is not the same as result. What a molecule does inside a cell is biology. What a supplement does for the person taking it is a separate question, and it needs its own evidence. We explain the first so you know what the word on the label means. We make no claim about the second.
Frequently asked questions
Which foods contain vitamin B3?
The NHS names meat, fish, wheat flour and eggs as good sources of niacin, which is vitamin B3. Foods that contain protein also provide tryptophan, which the body can convert in part.
Is nicotinamide the same as niacinamide?
Yes. They are two names for the same compound, one of the forms of vitamin B3. Nicotinic acid is a different form.
Do foods contain NAD+?
Many do, because they are made of cells that contain it. A review in Cell Metabolism notes that in animal products the NAD+ and NADP+ in the food's cells account for much of their niacin content. We make no claim about what happens to it after eating.
Sources
- NHS: B vitamins and folic acid
- NIH Office of Dietary Supplements: Niacin: Fact Sheet for Health Professionals
- Public Health England: Government Dietary Recommendations
- Cell Press, Cell Metabolism: NAD+ Metabolism and the Control of Energy Homeostasis: A Balancing Act between Mitochondria and the Nucleus
- Department of Health and Social Care: Great Britain nutrition and health claims (NHC) register
