Here’s what most of us know about Alzheimer’s: Symptoms include serious memory loss and confusion, and a buildup of brain plaque (beta-amyloid protein pieces) likely causes those issues. Yet that isn’t the full story; there are many other potential explanations for the disease’s existence. Some scientists, for instance, believe that neuronal stress (stress from diet, lifestyle, or genetics that affects brain cells) is the root cause, and plaques are simply a by-product of that stress. Others speculate that Alzheimer’s occurs when neurons (brain cells) stop producing and using energy correctly. The latter theory has generated buzz in recent months, because a new study found that a molecule called NAD+ helped neurons function normally. Thus, NAD+ may help slow the aging of neurons and reduce a person’s Alzheimer’s risk.
What is NAD+?
NAD+ stands for nicotinamide adenine dinucleotide. It’s a form of vitamin B-3 and a co-enzyme, or a molecule that aids an enzyme as it works (in fact, many vitamins are co-enzymes). NAD+ helps our cells get energy from the food we eat, and it also helps repair DNA and improve the function of immune system cells. All in all, it’s a vital part of our bodies, helping to maintain healthy tissue and a healthy metabolism.
As we age, our NAD+ levels tend to decline. (This may be for several reasons — from lifestyle changes to genetics.) Low NAD+ levels are linked to cognitive decline, diabetes, cancers, and frailty, and some researchers believe that supplementing with NAD+ can help slow down and even reverse certain conditions.
What happened in the study?
Published in Aging Cell, the study was conducted by a team of researchers at the National Institute on Aging (NIA) in Baltimore, Maryland. The NIA team hypothesized that boosting a person’s NAD+ levels with a supplement could increase levels of NAD+ in the brain and reduce the risk of neurodegenerative disease (any disease in which cells in the central nervous system malfunction — this includes Alzheimer’s). So, they analyzed data from a previous study conducted by University of Colorado (CU) researchers, during which adults around the age of 65 took a vitamin B-3 supplement called nicotinamide riboside (NR) twice daily for six weeks. (NR becomes NAD+ in the body.) Another group of participants received a placebo.
After six weeks, the CU researchers observed that participants taking the NR supplement experienced an increase in their NAD+ blood levels. In addition, the participants’ blood pressure decreased and arterial stiffness softened. (Stiff arteries lead to high blood pressure.)
With this in mind, the NIA team conducted a series of tests on the data which suggested that participants’ NAD+ in the brain also increased. This is important because not every supplement makes it to the brain. Certain nutrients cannot penetrate the blood-brain barrier — a network of blood vessels and tissues that filter out harmful substances before they reach the brain. While the NIA researchers couldn’t prove that the NR supplement crossed the blood-brain barrier, their data showed that it’s likely.
What effect did the NR supplement have on the brain?
The NIA team couldn’t show exactly how the NR (vitamin B-3) supplement affected the participants’ neurons. However, they gathered evidence to show that it positively altered pathways in the brain that are affected by Alzheimer’s. In addition, the NIA researchers noticed a small but significant decrease of tau and amyloid proteins in participants’ brains when compared to the placebo group.
In Alzheimer’s, abnormal tau and amyloid proteins collect between neurons and clump together — so reducing these proteins may be beneficial. In this study, it’s possible that the participants’ brains were able to function better with the NR supplement and could clear out excess proteins more easily.
How can I improve my NAD+ levels?
Nicotinamide riboside — the precursor to NAD+ — is found in cucumber, cabbage, broccoli, avocado, and tomato. Other foods that boost your NAD+ levels? Turkey, fish (sardines, salmon, and tuna), whole grains, milk, beef, pork, green vegetables (especially asparagus and peas), mushrooms, and nutritional yeast. If you’d rather take an NAD+ supplement, the recommended dosage is between 250 and 300 milligrams daily. (Note: Speak to your doctor before trying a new supplement.)
Also, the foods we eat influence the bioavailability of NAD+ in the body. A high fat, high sugar diet can cause NAD+ levels to decrease, so eating sugary and fatty foods in moderation may help improve your levels.
What does all of this mean for us?
Ultimately, there is much more to Alzheimer’s than we often realize. Future treatments for the disease may involve not just reducing plaque in the brain, but also “feeding” neurons with high-quality foods or supplements that boost levels of NAD+.
The cure may be in the far-off future, but improving your brain health and reducing your Alzheimer’s risk can start right now. If you want to learn more about protecting your memory and cognitive function, check out these tips to triple your memory in five minutes, and this neuroscience expert’s number one brain boosting hack.