These "Longevity Genes" Are Vital To Healthy Aging, From A Functional MD

You know that guy at work you thought was 50 and turned out to be 70? Or that woman in yoga class who seemed 40 until she introduced you to her 30-year-old kid? We wrote The New Rules of Aging Well to help you become like them. To let you in on the health habits of people who age amazingly well—who look great, feel well, and are energetic, happy, sexy, agile, and strong. It's not luck, and it's not something that's randomly bestowed on people. It's a result of specific life choices, and it's something anyone can have with motivation and commitment.

How you age has everything to do with the choices you make right now—what you eat and how active you are but also how you spend your free time and how you see the world around you. There's a lot to it, and yet in some ways it's simple: What you put into your body and mind affects the whole organism, determining function and resilience.

If you're not aging well, there are answers: elements you need to add to your daily life (certain practices, foods, supplements) and others you need to subtract (same list but different specs). Your body is a complex machine, and keeping it humming along beautifully as you age calls for a plan—one that preps your body to handle whatever the world throws at it.

If you're achy, tired, gaining weight, not sleeping well, pay attention: These are warning signs. Signals from your body to get your sh*t together while you still can.

This is not a drill. If you want your body to run well as you age, you can't be cavalier anymore about how you treat it. Otherwise, what can happen is that your organs and other systems underperform; this is what makes you feel physically terrible from day to day and weakens your immunity over time. The right choices can radically alter, and even reverse, some of the symptoms our culture has come to accept as normal signs of aging.

You have power in this situation. Some folks worry that they're destined to age a certain way because of the way their relatives did. Nope. The idea of "bad genes" creating your destiny is grossly exaggerated. You can look at your family and gather useful information. You can get genome testing and learn a lot. But this info is only the beginning of the story because lifestyle choices have a tremendous impact on whether certain genes turn on or off. Studies on identical twins prove this: How you age, in many ways, is up to you.

There are 20 or so genes that researchers have recently identified as "longevity genes"—those with the potential to help us live longer, healthier lives. Some you may have heard of the sirtuins AMPK and mTOR. The pathways of many of these longevity genes respond to lifestyle habits: what, when, and how much you eat; how you move your body; how much restful sleep you get; and how much stress you endure, among other things. Regulating these gene pathways up or down through healthy habits can extend your life span and expand your "health span"—the vitality level throughout your life—and that's what The New Rules of Aging Well is all about.

Recent research tells us that as we age, we should be getting more of our protein from plants and less from animals. It's about those longevity genes AMPK and mTOR, which are important nutrient sensors. mTOR controls a number of cell functions, including cell growth and cell proliferation. For younger people who are growing or whose bodies are in reproductive mode, mTOR has many benefits. But when we get older, we don't want to encourage cell proliferation (cancer is cell proliferation). The goal at this point is to inhibit mTOR. Animal protein, especially red meat, contains high amounts of branched-chain amino acids like leucine, which stimulate mTOR. Plant protein does not contain much of these amino acids, so it does not stimulate mTOR as much; mTOR also gets in the way of autophagy (the body's cell-cleaning function). So turn up the plant protein, and turn down the meat and dairy.

Protein can be tricky, because your needs change as you age—and because it's been drummed into our heads that more protein is always better (we all know that a high-protein, low-carb diet is good for weight loss). But between the ages of 45 and 65, it's more important to eat less meat and dairy than it is to go crazy with protein. A person in this age range weighing 150 pounds needs about 55 grams of protein a day. Most people get this amount without too much effort.

After age 65, protein becomes extremely important. At this point, your body needs more protein, to combat sarcopenia—loss of muscle mass—which is just a natural part of life. So you want to increase your protein intake by about 25%: A 150-pound person who's 65 or over should aim for about 70 grams of protein a day. This, combined with exercise, especially strength training, helps minimize the loss of muscle mass.

Is it better to increase your protein sooner, between the ages of 45 and 65? No. It's actually better not to, if your source, as it is for most folks, is meat and dairy. As we explain in the book, there are issues with animal protein. Once your body has changed from production mode to preservation mode (at about age 45), too much animal protein can support the growth of things you don't want growing.

The tipping point is around age 65. From 65 on, if you need to eat more animal products than you've been consuming to get the amount of protein you need, so be it. It's very important.