Professional athletes know it. Just ask tennis great Venus Williams, who joyously returned to the court after she became vegan to help treat her autoimmune disease, Sjogren’s syndrome.

Then there’s linebacker Wesley Woodward. He persuaded 10 other Tennessee Titans to switch to a plant-based diet the year the team made it to the playoffs after a decade of being out of the running.

What you eat transforms your mood, your energy and your motivation. Body and mind are intertwined. Research confirms what you’ve felt in your muscles, bones and brain.

A new study published in Psychosomatic Medicine looked at 16 studies covering 46,000 people and found that weight-loss, nutrient-boosting and fat-reduction diets can slash symptoms of depression. Eating more nutrient-dense, high-fiber, veggie-centric meals helps you get free from the psychologically negative effects of a junk-food diet.

With the epidemics of obesity, poor nutrition, lack of physical activity and chronic pain that are engulfing the U.S., that’s a lot of fuel for the blues. So if you’re feeling down in the dumps, it’s time to look at what you’re putting into your body.

TAKING A BITE OUT OF DEPRESSION

In “What to Eat When,” Dr. Michael Roizen and Dr. Michael Crupain lay out the smart, long-term approach to food that will help protect you from depression and boost your health in different ways, reducing the risk of many cancers; diabetes; joint, sexual and memory problems!

Your sources for mood-lifting, nutrient-dense, high-fiber protein:

>> If you don’t go vegetarian or vegan, stick with fish that deliver a good dose of healthy omega-3 fatty acids: salmon, sea trout, herring, sardines. Studies indicate that omega-3s help improve the function of neurotransmitters, which may boost or protect your mood.

>> Rely on plant-based proteins and protein builders. They include: 100 percent whole grains (wheat, sorghum, teff, barley, farro, corn, millet, oats, etc.); beans of all kinds, lentils, chickpeas, soy/tofu; nuts and nut butters; peanuts, which are loaded with tryptophan — a building block of serotonin, which is a neurotransmitter that is in short supply in folks with chronic depression; and colorful veggies such as broccoli, spinach, asparagus, artichokes, potatoes, sweet potatoes and Brussels sprouts.

>> Keep green tea nearby. One of its many benefits is how it calms you by easing stress responses that can fuel the blues.

OTHER SMART STEPS

Minor depression causes you to have symptoms for longer than two weeks at a time, but does not meet the criteria for major depression. However, about 16 million American adults contend with Major Depressive Disorder and only about two-thirds are receiving treatment.

Both regular exercise and good nutrition are essential components of a healthy mind and body, and you do not want to risk serious health problems associated with chronic depression, such as heart disease, diabetes, self-injury or attempted suicide. (Four percent of folks 18 and older report that they had thoughts about suicide in 2016.)

So, if your blues persist, talk with your doctor, seek talk therapy, join an in-person or online support group (check out the Anxiety and Depression Association of America and the National Alliance of Mental Illness online to find support) and tell a friend or family member.

If you are that friend or family member, take steps to get your near and dear help.

Mehmet Oz, M.D., is host of “The Dr. Oz Show,” and Mike Roizen, M.D., is Chief Wellness Officer and Chair of Wellness Institute at Cleveland Clinic. Email questions to youdocsdaily@sharecare.com.