Research suggests our fate lies in our microbiome: Many of our daily decisions about and interactions with food, personal-care products, and environmental factors influence how happy or unhappy these cells will be in their home. The health of our gut microbiome largely determines how we will age and the diseases we will either acquire or avoid.

In a recent study, women who exercised regularly throughout their lives decreased their chances of developing dementia by 90 percent, compared to those who didn’t routinely exercise. It doesn’t have to be much. It’s great to aim for around 3,000 to 4,000 steps—or one to two miles—per day. Moreover, in the group of exercisers, if they went on to develop dementia, it appeared on average eleven years later than it appeared in the group that did not exercise.

If there were a drug that were 90 percent effective in stopping dementia, how much would we pay to take it? That drug is actually probably sitting at your feet wagging its tail wanting to go for a long walk (hint: It’s your dog). In my office, I even write prescriptions for people to get a dog, and many patients say it’s the best prescription anyone has ever given them.

I was a professor at a university in one of the world’s best-known and only blue zones in America—Loma Linda, California. Loma linda means beautiful hill in Spanish; a commonality among all the blue zones is that all of the communities live on hills. I tell my patients an easy trick if you’re in a building: If going up the stairs is too hard or you don’t want to break a sweat going to the big meeting, ride the elevator up and then walk back down.

Recent research has shown that exercising for as little as thirty minutes a day can change the gut microbiome for the better. This would include things such as yoga, walking your dog, or even gardening or meditation. However, certain exercises, such as long-distance running, can damage and even scar the heart muscle.

The brain has a newly discovered glymphatic system that is responsible for washing toxic substances and proteins, like amyloid, out of the brain. This wash occurs during deep sleep, which usually happens early in the sleep cycle. Deep sleep is different from REM sleep, which is when we dream and can actually consolidate the things that we’ve learned. We used to think that REM was the most important part of the sleep cycle, but it’s probably more important to clean your brain. Deep sleep is the first stage of sleep and comes before REM sleep. In terms of cleaning your brain, deep sleep is more important. Increased blood flow to the brain is needed during this time.

As a general rule, the greater the time between eating your last meal and going to bed, the more blood flow will be directed to your brain versus your gut. (If you eat close to bedtime, blood is diverted to your intestines to aid in digestion.) Try to finish dinner three to four hours before bedtime. No snacking in between finishing dinner and bed. Start by doing this once a week and build up from there. If you can, try making your dinnertime earlier to extend your period of restricted feeding.

When you practice intermittent fasting, the body sends signals to the cells that there isn’t much energy to work with and they need to recycle existing parts. Those signals promote autophagy and mitophagy: cellular and mitochondrial self-cleaning in which dysfunctional components are recycled or removed. And it turns out this process is really great for you: If a dysfunctional cell doesn’t recycle its parts, it eventually bursts, and the loose cellular materials are capable of causing inflammation in the body. It’s autophagy, this clearance of cellular debris, that’s the new vanguard in anti-aging research.

Mushrooms contain an antioxidant called ergothioneine, which has been shown to diminish the risk of dementia. Aim for two cups of mushrooms per week. Mushrooms also contain a high level of polyamines, which are longevity-promoting compounds.

Nuts do wonderful things for your microbiome and have been shown to lower the risk of cancer. I recommend walnuts, macadamia nuts, hazelnuts, and pistachios.

Cruciferous vegetables, especially broccoli, cauliflower, and Brussels sprouts, benefit the gut, are rich in antioxidants, and have anti-inflammatory properties.

Lentils also contain polyamines.

Olive oil has been shown to actually grow neurons in humans, and research suggests it can help prevent or slow the development of dementia. It has anti-inflammatory properties due to its high level of polyphenols.

Fermented foods, like sauerkraut, are a great source of polyamines.

Green tea contains a powerful polyphenol called EGCG. This antioxidant works to slow aging, keep inflammation at bay, and extend lifespan.

Avoid: The real killers are simple sugars and foods that rapidly convert to sugars, saturated animal fats, and most animal proteins. The one factor that unites the blue zones is that the people who live in them all eat very little animal protein. Lectins are another one to avoid because they are one of the major reasons that our gut wall is broken down, and one of the major determinants of aging is the breakdown of the gut wall.