What’s the upper safe dosage for niacin (vitamin B3)?

The upper safe dosage for niacin is 35 mg for adults. We should get higher doses found in dietary supplements only under medical supervision, as doses higher than the safe limit may cause serious adverse effects! Consuming a wide variety of foods rich in niacin won’t cause niacin toxicity, though.

Health benefits of niacin (vitamin B3)

Niacin is a water-soluble B-vitamin, also known as vitamin B3. It’s crucial for good health.

For instance, niacin is necessary for a healthy heart. It improves endothelial function (the thin membrane inside the heart and blood vessels), reduces atherosclerosis progression, and prevents vascular inflammation.[1,2,3]

Also, niacin increases High-Density Lipoprotein (HDL) cholesterol, while reducing Low-Density Lipoprotein (LDL) cholesterol and triglycerides! Hence, niacin is usually used for the reduction of high cholesterol levels. Pharmacological doses between 1,000 and 3,000 mcg have beneficial effects.

In fact, niacin has been found to decrease cardiovascular mortality. Especially, when used in combination with statin drugs.

Moreover, niacin has a neuroprotective effect. It plays a key role in the proper functioning of the central nervous system. Thus, niacin may decrease the risk of age-associated neurological disorders, such as Alzheimer disease, or Parkinson disease.

Additionally, niacin is beneficial for people with diabetes, chronic kidney disease, and arthritis.

Last, but not least, adequate amounts of niacin are necessary for weight loss. Niacin improves insulin sensitivity and plays a key role in the regulation of circadian rhythm and metabolism!

What’s the recommended daily intake?

The recommended daily intake for niacin is 16 mg for men and 14 mg for women. Only pregnant and lactating women need higher doses of 18 mg and 17 mg, respectively.

What’s the upper safe dosage for niacin from supplements?

The upper safe dosage for niacin from supplements is 35 mg for adults, 30 mg for teenagers, and 10-20 mg for children, depending on the age. Skin flushing is the most common side effect for higher doses.

But, patients could safely receive much higher doses under medical supervision. Even extremely high doses of 4,000 mcg a day are almost completely absorbed.

Certainly, you should consult your physician before taking niacin supplements. Especially, if you’re pregnant, take medication, or have a medical condition.

Can I get too much niacin from food?

On the contrary, there isn’t an upper safe dose for niacin from foods. Following a diet high in niacin won’t cause any adverse effects.

In fact, there is a wide variety of foods high in niacin. Animal-based food sources high in niacin are turkey, beef, and fish. These foods provide about 5-10 mg of niacin per serving.

Beans, seeds, nuts, whole grains, mushrooms, and nutritional yeast are excellent plant-based sources of niacin. They provide about 2-5 mg of niacin per serving. Nutritional yeast is among the richest foods in niacin. It provides 15 mg of niacin per serving!

Moreover, there are many fortified foods rich in niacin, which boost the daily intake. Most noteworthy, fortified foods contain niacin in its free form, which is highly bioavailable.

Adverse effects of high dosages.

Most niacin supplements contain between 50-500 mg of niacin per serving. But, a dose of 500 mg is about 3,000% and 1,300% higher than the recommended daily and maximum safe dose, respectively!

Even smaller niacin doses of 50 mg in the form of nicotinic acid may cause skin flushing, as it increases the blood flow of small subcutaneous blood vessels. The flushing may be accompanied by a burning or itching sensation.

But, more serious side effects may occur. For instance, headache, rash, dizziness, and a decrease in blood pressure are common side effects of niacin overdose.

Above all, if you experience adverse effects, you should immediately talk to your health care provider. Furthermore, you should decrease the daily dose. Also, if you take niacin supplements in the form of nicotinic acid and experience side effects, you could take them with food.

Additionally, much higher doses of 3,000 mg a day may cause more serious adverse effects, such as impaired glucose tolerance, insulin resistance, nausea, heartburn, abdominal pain, and even blurred vision.

Hence, you should take these pharmacological doses only under medical supervision.

Moreover, the American College of Cardiology and the American Heart Association recommend measuring hepatic transaminase, fasting blood glucose, hemoglobin A1C, and uric acid levels before starting therapy with extremely high doses of niacin.

Furthermore, if you take extremely high doses of niacin supplements, you should avoid alcohol. It seems to increase the risk of flushing. Also, people who overconsume alcohol for years shouldn’t take high doses of niacin, as it may further damage their liver!

Last, but not least, pregnant women shouldn’t take high dosages of niacin, without consulting their physician. High doses of niacin may harm the fetus.

What type of niacin supplement has fewer side effects?

Niacin in dietary supplements is mainly found in two forms; nicotinamide and nicotinic acid. High doses of both niacin forms can cause adverse effects, though.

As a rule of thumb, nicotinamide is more tolerable than nicotinic acid. The same dosage has fewer adverse effects than nicotinic acid. For instance, it doesn’t cause skin flushing.

Side effects, such as nausea and vomiting, may occur at extremely high nicotinamide intakes of 3,000 mg per day, though.

In any case, you shouldn’t exceed the upper safe dose for niacin without consulting your physician.

Do I need niacin supplements?

Healthy people who follow a well-balanced diet don’t need niacin supplementation.

On the other hand, poor diet, alcohol abuse, medication, and disease are common reasons of niacin deficiency.

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