Niacin (Vitamin B3): A Practical Guide
Niacin (vitamin B3) enables your body to convert the food you eat to energy and is required by every part of your body for optimal function.
- Because niacin is critical for energy utilisation, it can help lower cholesterol, ease arthritis and boost brain function.
- Niacin is a precursor of NAD and NADP, two coenzymes involved in cellular metabolism and the movement of energy around your body.
- Niacin plays a role in cell signalling, creating and repairing DNA as well as acting as an antioxidant.
Your body gets niacin through food but also makes small amounts endogenously from the amino acid tryptophan.
Niacin deficiency symptoms
Symptoms of niacin deficiency include:
Severe niacin deficiency (pellagra) usually only occurs in developing countries where diets are not as varied.
Niacin storage in your body
Niacin is water-soluble. Your body doesn’t store it for long, so you need to consume niacin containing foods regularly. However, the fact that niacin is water-soluble means that your body can easily excrete excess niacin.
Functions of niacin
You need adequate niacin to:
- break down your food,
- build and grow your muscles,
- detoxify your body,
- recycle other nutrients (e.g. vitamin K and folate),
- manage oxidative stress,
- use neurotransmitters in your brain,
- repair your DNA, and
- lengthen your telomeres (an indicator of aging and longevity).
The increase in NAD+ and sirtuins seems to be one of the reasons that calorie restriction and fasting help to repair our body and delay the diseases of aging. Hence, focusing on higher satiety nutrient-dense foods and meals is crucial to delaying the diseases of ageing.
Niacin is a precursor to NAD+, so obtaining adequate vitamin B3 in your diet is critical to keeping your body feeling young and energised for longer.
Factors that will increase your demand for niacin
You may need more niacin if you:
- consume excessive amounts of alcohol,
- eat a lot of sugar,
- have diarrhoea,
- have a fever,
- have high cholesterol,
- are going through a growth spurt,
- consume a low protein diet,
- eat a lot of refined foods,
- are a smoker,
- have schizophrenia, or
- have ulcerative colitis.
How much niacin is required daily?
Our satiety analysis of data from Optimisers suggests that foods with more niacin (vitamin B3) tend to be more satiating on a calorie for calorie basis up until around 80 mg per 2000 calories. People who eat food that contains more niacin tend to consume about 29% fewer calories.
The average niacin intake of Optimisers is 44 mg per 2000 calories, with an 85th percentile value of 70 mg/2000 calories. This is significantly higher than the Estimated Average Requirement (EAR) of 11mg/day and Dietary Reference Intake (DRI) of 16 mg/day.
At high doses of 3 – 4 g per day, niacin is still absorbed into the bloodstream to create NAD+ and add to the circulating pool of niacin. This may be useful if you have been fasting for an extended period to enable your body to replenish your niacin stores quickly. However, it doesn’t seem that we crave any more of it beyond that point on a day to day basis.
Regular supplemental doses greater than 80 mg/day doesn’t seem to provide any additional benefit (at least in terms of satiety and reducing cravings). Higher supplemental doses of niacin will be quickly excreted by the kidneys into the urine.
Niacin stretch target
Based on our satiety analysis, we recommend a stretch target for niacin of 70 mg/day for men and 56 mg/day for women.
|nutrient||average||EAR||DRI||stretch (men)||stretch (women)|
|niacin (B3) (mg)||44||11||16||70||56|
Availability of niacin in the food system
As shown in the chart below, the availability of niacin in the food system has increased with the fortification of breakfast cereals and bread (data from USDA Economic Research Service). While you will be able to to meet the Recommended Daily Intake for niacin with commonly available foods, you will need to pay particular attention to achieve optimal niacin levels from food.
Excess B3 side effects: the niacin flush
The Upper Limit intake for niacin has been set at 35 mg/day due to the niacin flush response you will get if you take large doses of supplemental niacin (which is absorbed more quickly than from food). This flushing is harmless but can be uncomfortable and surprising. It’s a bit like an internal sauna.
Supplementation of high doses of B3 will slow lipolysis and gluconeogenesis (i.e. the release of energy stored fat and glucose from your body into your bloodstream) because it sends a “full signal” to the body. If you do choose to supplement Vitamin B3, don’t take it just before a workout because it will limit your energy availability.
If you do decide to take B3 supplements, start small at 25 mg/day and see what happens before ramping up to higher doses. Excessive supplemental niacin may cause insulin resistance and impaired glucose tolerance (i.e. diabetes).
High dose niacin supplementation (for management of diabetes, cholesterol, etc.) should only be done under the supervision of an experienced health practitioner who can monitor changes in your cholesterol, insulin and glucose levels over time.
Niacin works synergistically with vitamins B1, B2, B6, B12, C, chromium, zinc, potassium manganese, phosphorus, copper, folic acid, iron, magnesium methionine, selenium and tryptophan. Hence, it is important to get your calcium from whole food sources that typically come packaged with these other nutrients.
Niacin rich food sources
Popular foods that contain more niacin include both vegetables and animal sources such as:
The nutrient fingerprint below shows the availability of nutrients in the foods that contain the most niacin. Niacin is relatively easy to obtain in adequate quantities from nutrient-dense foods and meals. Foods that contain more niacin typically contain more protein.
Nutritious foods and meals to boost your Vitamin B3
If you are experiencing any of the symptoms of low vitamin B3 or are concerned that your current vitamin B3 intake is low (e.g. due to a heavily grain-based processed diet with less protein), then you may be interested in our lists of vitamin B3 rich foods and meals.
What you will get:
- Our Nutritional Optimisation Kickstart Guide.
- A list of the most popular 50 foods that contain more Vitamin B3.
- A longer list of 100 popular foods that contain Vitamin B3.
- A still longer list of 150 common foods that contain Vitamin B3 to allow you to expand your nutrient-dense repertoire further, and
- An index of 150 nutrient-dense recipes that provide more Vitamin B3.