WARNING!
This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.
The human body needs nutrients to survive. One piece of the puzzle is a water-soluble nutrient, vitamin B3. Deficiency may happen if you don't eat foods rich in vitamin B3; if you have dysfunctional absorption or a metabolic disorder; or if you’ve used chemotherapeutic agents for a long time.1
The vitamin’s common name is niacin and it's a precursor to nicotinamide adenine dinucleotide (NAD), which is used to catalyze more than 400 enzymatic reactions in the body.2 NAD is necessary for activities to repair DNA, and it’s essential for genome stability. The precursors to NAD are collectively called niacin. These are nicotinic acid, nicotinamide and nicotinamide riboside.
Tryptophan is an essential amino acid that can be converted into NAD in the liver. Once formed, NAD can be altered to other necessary forms — nicotinamide adenine dinucleotide phosphate (NADP), nicotinamide adenine dinucleotide (NADH) and nicotinamide adenine dinucleotide phosphate (NADPH).
Many animal-based foods are high in niacin, including pastured beef and poultry as well as wild-caught Alaskan salmon. These have higher amounts of bioavailable niacin than plant-based foods such as nuts and legumes.
According to the American Cancer Society, there are more than 16.9 million people in the U.S. who had cancer and were alive on January 1, 2019. It’s expected that more than 1.8 million more cases will be diagnosed in 2020.3
The traditional view of cancer is that it's a genetic disease. The American Cancer Society writes that just 42% of all cases are potentially avoidable. Yet, there is strong evidence that the genetic mutation found in cancer is a downstream effect of defective energy metabolism in the mitochondria, and not the primary source of cancer.4
Vitamin B3 Helps Slow Growth of Glioblastoma
Vitamin B3 also plays a significant role in the immune system. Researchers screened 1,040 compounds before testing niacin for the role it may play in helping the body fight glioblastoma.5 Glioblastoma is one of the more common brain tumors, and it’s the most lethal.6
Approximately 180,000 people in the U.S. are diagnosed with a glioblastoma each year, and once diagnosed most people live less than 15 months.7 Scientists think the reason a glioblastoma is so lethal may be attributed to brain tumor-initiating cells (BTICs) with stem cell-like properties.
These cells are adaptable and can turn the body’s macrophages, microglia and monocytes into promoting tumor growth instead of fighting it. In laboratory experiments, researchers found niacin could invigorate monocyte cells into once again fighting BTICs.
Building on this knowledge, the researchers conducted an animal study8 to test the effectiveness of niacin against cancer. When treated, the life of the mice was extended, and when used in combination with chemotherapy the results were even better. In the mice receiving the combination therapy, the life span increased from 40 days to 150 days.
One of the researchers, Wee Yong, Ph.D., from the University of Calgary’s Cumming School of Medicine, is encouraged by the results. While speaking to Inverse, he called the ability of niacin to help suppress brain cancer cells “remarkable,” and hopes this information will help spur other advances in the treatment of glioblastoma:9
“While it’s not a cure, it’s a promising step forward against this incurable disease. The brain tumor stem cells for glioblastoma have been very resistant to treatment, so instead of targeting those cells, we targeted the immune system to help the body to attack and destroy the stem cells.”
Research Shows Niacin Effective in Other Cancer Types
Researchers have been studying the effects of niacin and cancer for nearly three decades.10 In that time they’ve made some interesting discoveries, including the effect niacin has on the prevention,11 development12 and treatment of cancer.13
In one study14 researchers sought to evaluate the effect of niacin on serotonin-producing neuroendocrine tumors. The researchers engaged patients with these tumors, who were given niacin supplementation alongside healthy patients in a control group who did not receive the treatment.
Niacin levels were measured before and after the intervention. They found deficiency was prevalent and supplementation was effective in normalizing levels. However, the patients were not followed long-term, so no determination was made as to effects over time. The scientists suggested a prospective study should be done.
In another study,15 scientists found that the combination of loperamide (Imodium), a drug used to slow the effects of diarrhea, with niacin improved biochemical measurements in rats with liver cancer.
Cancer Is a Metabolic Disease
Each day more than 1,600 people in the U.S. die from cancer.16 Many of these deaths are unnecessary as they are preventable and treatable with the right therapies. Thomas Seyfried, Ph.D., is a pioneer in the application of nutritional ketosis for cancer, which we discuss in this short video.
His therapy stems from work done by Dr. Otto Warburg, who received the Nobel Prize for Physiology or Medicine in 1931 for his discovery of the metabolism of malignant cells. Following in Warburg's steps, Seyfried has spent years conducting research to advance the science. Mitochondria were not well understood during Warburg's time.
But advancements in technology have improved the appreciation of how they function. Seyfried sets the stage by pointing out that all major college texts identify a genetic base for cancer growths. This idea pervades the pharmaceutical and academic industries as well, driving research and quashing discussions of alternative views. He points out:17
“The argument now is that, yes, metabolic problems occur in cancer cells. No one denies that. But these are all due to the genetic mutations. Therefore we must maintain ourselves on the established track that all of this metabolic stuff could be resolved if we just understood more about the genetic underpinning of the disease.
Now that would be well and good if it were true. But the evidence is accumulating that the mutations we see that are the prime focus and the basis for the genetic theory are actually epiphenomenal. They're downstream effects of this disturbance in the metabolism that Warburg originally defined back in the 1920s and '30s."
A change in focus in the development of cancer would alter cancer treatments. If defective mitochondria are responsible for malignant growths, then treatment should include improving mitochondrial function. As Seyfried points out, inherited mutations may also impact mitochondrial health, and thus the development of cancer.
In “Top Tips to Optimize Your Mitochondrial Health” I explain why becoming an efficient fat burner is so important to supporting mitochondrial health. I also talk about the difference between healthy ketosis and diabetic ketoacidosis.
Niacin Necessary for Cognitive Health
The connection between niacin and brain and nervous system health is well established. Your nervous system requires adequate nutrition to maintain and optimize cognitive health and function. For instance, omega-3 fats — in particular, DHA — are vitally important to brain health.18 Specific vitamins are also important, and deficiencies are associated with cognitive decline.
If you become deficient, the most common symptoms involve your nervous system, skin and digestive system. The symptoms are referred to as a triad of the “three D’s” — sun sensitivity dermatitis, diarrhea and dementia.19 The fourth, when left untreated, is death.
Two of the neuropsychiatric clinical signs are delirium and dementia. Schizophrenia also shares some of the symptoms of pellagra, a condition caused by niacin deficiency.20 Other B vitamins may also contribute to neuropsychiatric symptoms, including deficiencies in B1, B2, B6, B8 and/or B12.
The authors of one study21 found that the intake of B vitamins during young adulthood improved cognitive function during midlife, demonstrating the long-lasting effects of good nutrition.
Another group of researchers22 gathered data from 3,718 Chicago residents over the age of 65 who completed a nutrient questionnaire and underwent four cognitive tests at three-year intervals. The data revealed those with the highest niacin intake had the greatest protection against Alzheimer's disease and age-related cognitive decline.
How Niacin Flush Develops — Is it Dangerous?
Most people who use niacin supplements do so to help reduce their cholesterol levels. The supplement they use is nicotinic acid, which has a side effect called niacin flush. To reduce the potential of experiencing the side effect some choose to use niacinamide.23
Symptoms of a niacin flush begin with tingling or burning sensation in the face, neck and chest. The skin turns red or flushed and the skin may feel warm to the touch.24 Niacin triggers dilation of the blood vessels near the skin along with symptoms of the reaction.
Over time, you may develop a tolerance, which reduces this effect. Although it is irritating and may be disturbing if you don’t expect it, a niacin flush is harmless. There are steps you can take as your body builds a tolerance, such as using smaller doses throughout the day, using a time-released version, taking it with meals and drinking plenty of fluid with the supplement.
Alternate Vitamin B3 Supplement Has Different Benefits
An alternate supplemental form of vitamin B3 is niacinamide, which is a form of niacin combined with an amino acid like tryptophan. Niacin and niacinamide are similarly effective in the body but their pharmacological properties are different.
Natural niacin and niacinamide can be obtained from your food; unlike supplemental niacin, these do not cause flushing. However, since it is a water-soluble vitamin, it’s not stored and instead is eliminated through the kidneys.
Niacinamide regulates cell regeneration, which makes it a popular ingredient in anti-aging products.25 For more about niacinamide studies, dosage and side effects see “Niacinamide: Get to Know More About This Form of Vitamin B3.”