After a certain age, not many of us look forward to our next birthday with the same level of enthusiasm we once did. If there were a switch we could flip to slow down the aging process (to counter the waning energy, to keep those memories sharp, to stay healthy enough to continue having amazing experiences), then we'd probably all flip it in a heartbeat.
The good news: There is something scientists have identified that may be the key—or at least part of it—to keeping your mind and body aging in a healthy way. It's a coenzyme called nicotinamide adenine dinucleotide (NAD+), and it's starting to generate some buzz.
What is nicotinamide adenine dinucleotide (NAD+)?
NAD+ is a coenzyme, or molecule, found in all living cells, and it plays a vital role in energy metabolism and maintaining proper cell functioning. It is particularly crucial for the functioning of our mitochondria, the power plants in our cells that turn our food and oxygen into energy. The problem is that our levels of NAD+ decline significantly as we get older1 (impairing mitochondrial functioning, among other things), and these declining levels drive the aging process. Which makes sense when you consider that underperforming or damaged mitochondria2 are thought to contribute to a number of age-related health conditions.
One way NAD+ seems to exert its health-promoting properties is by helping sirtuins do their job3. Sirtuins are a class of proteins that regulate biological pathways, turn certain genes on and off, and help protect cells from age-related decline. For example, NAD+ increases the activity of one type of sirtuins, SIRT14, which has been found to induce the formation of new mitochondria and extend life span, as well as SIRT65, which helps maintain the length of telomeres (the end caps on DNA)—longer telomeres are associated with longevity.
Potential benefits of maintaining healthy NAD+ levels.
According to Ilene Ruhoy, M.D., Ph.D., an integrative neurologist and mindbodygreen health expert, "Appropriate levels of NAD+ are critical to support the body's response to stress, as NAD+ is used by these enzymes to modulate cellular activity in response to extrinsic and intrinsic assaults, including those triggered by environmental toxins, pro-inflammatory foods, trauma, and even chronic use of medication. NAD+ is essential for continued health, wellness, and strength."
Animal studies have shown that supporting healthy levels of NAD+6 can lead to improved memory, resistance to weight gain, a longer life span, and other benefits. As mentioned above, NAD+ is able to do this by activating proteins called sirtuins and optimizing cell metabolism in other ways. Here are some of the most promising ways that maintaining or increasing healthy NAD+ levels can improve health:
1. Combat age-related memory loss.
NAD+ is vital to DNA repair and resistance to neuronal stress. Because of this, it help enhance memory and slow down age-related memory loss. According to a recent animal study7, researchers developed a strain of mice with features mimicking human age-related memory decline, then added an NR supplement to their drinking water for three months to increase NAD+ levels. Over this period, researchers found that the NR-treated mice had less DNA damage, higher neuroplasticity, increased production of new neurons, and lower levels of neuronal damage. In the hippocampus area of the brain (where damage and loss of volume is found in people with memory issues), NR seemed to clear existing DNA damage or prevent it from spreading farther. The NR-treated mice also performed better on memory tests.
2. Counter high-fat diets and help manage weight gain.
Animal research suggests that increasing your levels of NAD+ may help support metabolism and weight maintenance, even if your diet is high in fat. One study8 found that mice on high-fat diets that received an NR supplement gained 60 percent less weight than they did on the same diets without NR. They also had more energy. These positive results, researchers say, were due to increased activation of the sirtuins SIRT1 and SIRT3, which led to improved oxidative metabolism.
3. Enhance strength and endurance.
As we age, muscle function and strength tend to decline. But according to animal studies, increasing NAD+ levels by supplementing with NR seems to help. In one study, researchers used mice whose genes were altered so their muscle tissue contained just 15 percent of the normal amount of NAD+. They then measured muscle strength and endurance, which was quite low. But after giving the mice NR-enriched water to replenish NAD+ levels, their exercise capacity was restored to that of a normal, healthy mouse in just one week. In another study, supplementation with NAD+ precursors led to DNA repair and an improvement in the health of muscle tissue within the first week—to the point where researchers couldn't tell the difference between the tissue of a mouse that was two years old and a mouse that was four months old.
4. Promote longevity.
Several studies9 have found that replenishing levels of NAD+ with supplements containing NR lengthen the life span of mice by improving mitochondrial function and increasing activation of SIRT110, a specific sirtuin protein. This is the same mechanism by which restricting calories seems to lengthen life span. (Additional compounds that may mimic the life-extending effects of calorie restriction include pterostilbene and resveratrol.) Other studies suggest that NAD+ increases the activation of SIRT65, which helps maintain the length of telomeres—the end caps on DNA that are associated with longevity.
How to maintain healthy NAD+ levels in the body.
Knowing this, we want to try to keep NAD+ levels in a healthy place, especially since we know that they decline naturally as we age. But here's the catch, taking an NAD+ supplement might not actually be the best way increase NAD+ levels in the body. This is because NAD+ is a large molecule11, so in order for NAD+ to enter your cells and get to work, your body has to take it apart, transport it piece-by-piece into the cell, and then put it back together again. But if NAD+ is not a nutrient present in food or practical to take by supplement, then why are we even talking about it? Turns out, there are a couple of indirect ways to increase your NAD+ levels, which may have positive results for your health:
1. Calorie Restriction
Restricting calories12 (20 to 30 percent less than what you normally consume) and fasting13 have been shown to increase NAD+ levels and increase activation of SIRT1. This SIRT1 activation, scientists say, is why calorie restriction has been associated with increased life span in animal studies. However, drastically cutting your calories or fasting for prolonged periods of time isn't realistic or advisable for most people. There is some speculation that intermittent fasting diets and low-carb ketogenic diets14 might have a similar impact on NAD+ levels15—while being much more sustainable—but more research needs to be done to confirm this.
2. Supplements containing nicotinamide riboside (NR)
Nicotinamide riboside (NR) is a newly discovered form of vitamin B3, which is found in trace amounts in milk. No one really thought much about NR until scientists discovered that our bodies convert NR into NAD+. Two recent human trials on NR-containing supplements found that they both effectively increased levels of NAD+16 in the body, which is promising. More studies are needed, but it looks like NR could be the future of healthy aging research.
3. Preventive measures to maintain healthy NAD+ levels
Additionally, there are some things you can do that can help maintain NAD+ levels—even if they don't necessarily increase them. For example, UV rays damage skin cells and your body uses NAD to repair that damage. Therefore, wearing sunscreen or protective clothing can help minimize that damage and preserve NAD+. A healthy, whole-food-based diet and a regular exercise routine (especially HIIT-type workouts) can't hurt, either—as they both boost the health of your mitochondria and help your body use NAD+ more efficiently or sparingly.
The bottom line on NAD+ and your health.
NAD+ is clearly an important molecule for optimizing a variety of cellular functions that promote overall health and longevity. While restricting calories is a natural way to increase NAD+ levels, it's likely not realistic for most people. Supplementing with an NAD+ precursor supplement such as NR, on the other hand, may be easier, and seem to be the next promising thing in healthy aging supplementation.
Stephanie Eckelkamp is a writer and editor who has been working for leading health publications for the past 10 years. She received her B.S. in journalism from Syracuse University with a minor in nutrition. In addition to contributing to mindbodygreen, she has written for Women's Health, Prevention, and Health. She is also a certified holistic health coach through the Institute for Integrative Nutrition. She has a passion for natural, toxin-free living, particularly when it comes to managing issues like anxiety and chronic Lyme disease (read about how she personally overcame Lyme disease here).