High levels of dietary niacin may significantly reduce the risk of cognitive decline

Extraordinary Machine

Think of your body as a machine. Now imagine this machine is the size of a gymnasium, packed wall to wall and floor to ceiling with countless minute systems that operate independently but are indispensable to the complex workings of larger interconnected functions.

In one of those minute systems, a gene called Silent Information Regulator 2 (SIR2) produces a protein that forms a protective barrier around cells, defending them from rogue DNA molecules that cause genetic instability. Without SIR2’s protein barrier, cells deteriorate and eventually die, unable to resist disease or invasion by foreign bodies. The result: the body ages.

Niacin (also known as vitamin B-3) helps regulate SIR2. And according to a study conducted by Chicago’s Rush Institute for Healthy Aging, high levels of dietary niacin may significantly reduce the risk of cognitive decline.

Eating and thinking

Discussing the Rush Institute study with Reuters Health, the lead author, Martha C. Morris, M.D., noted that very high therapeutic doses of niacin have been associated with a reduced risk of cognitive decline, such as Alzheimer’s, but no studies have examined the association between AD risk and the dietary intake of niacin.

Dr. Morris and colleagues recruited subjects from a Chicago community in which all the residents were over the age of 65. More than 3,700 subjects supplied detailed food frequency questionnaires, and during a study period that lasted more than five years, a series of cognitive tests were conducted periodically. The researchers randomly selected 815 subjects for close analysis. All in this group were free of AD at the outset. By the end of the study period, 131 of these subjects were diagnosed with the disease.

After evaluating the data, the Rush Institute team found a clear association between niacin intake and reduced cognitive decline and AD risk. Dr. Morris told Reuters that when subjects with the highest niacin intake were compared to those with the lowest intake, the high niacin group had an 80 percent reduction in risk.

This risk reduction was seen primarily in dietary intake. The protective effects of niacin supplements were not as strong.

Meat on the plate

The importance of niacin is well known to HSI members. In previous e-Alerts and Members Alerts, we’ve told you how niacin may help lower triglycerides while raising HDL cholesterol. Jonathan V. Wright, M.D., has also noted that niacin is effective in treating degenerative arthritis, anxiety, and type 1 diabetes.

Clearly, a good intake of niacin is essential to good health. So, with dietary sources getting high marks from the Rush Institute, what are the best food sources of niacin?

According to the Feinberg School of Medicine at Northwestern University, you’ll generally find niacin in high-protein foods. Here are some of the best sources:

• Beef liver, 3.5 oz cooked: 14.4 mg
• Peanuts, 1/2 cup: 10.5 mg
• Chicken (white meat, cooked): 13.4 mg
• Tuna (canned in water 3 oz): 11.8 mg
• Salmon (3.5 oz, cooked): 8.0 mg
• Ground beef (3.5 oz, cooked): 5.3 mg

The Feinberg report notes that adults need a minimum of about 15 mg of niacin each day.

One note of caution

Some people may have a reaction to niacin supplements. Higher doses can sometimes cause the infamous “niacin flush,” where you get a brief sunburn-like redness and itching sensation.

Therapeutic doses of niacin – as much as 2 grams, three times daily – are sometimes used to address high cholesterol. This is the type of dose that causes the niacin flush, which may cause problems for asthma patients and people with peptic ulcer disease. Prolonged doses at this level may also prompt toxicity to the liver. So anyone who puts niacin supplements to use at higher than normal dosages should consult with a doctor, naturopath or nutritionist.

Sources:
“Dietary Niacin and the Risk of Incident Alzheimer’s Disease and of Cognitive Decline” Journal of Neurology, Neurosurgery, and Psychiatry, Vol. 75, No. 8, August 2004, ncbi.nlm.nih.gov
“Niacin May Protect Against Alzheimer’s” Anthony J. Brown, M.D., Reuters Health, 7/15/04, reutershealth.com
“Nutrition Fact Sheet: Niacin (vitamin B3)” Feinberg School of Medicine, Northwestern University, feinberg.northwestern.edu