Doctor’s Tip: What we eat can affect our mood
Last week’s column presented an overview of depression. Mention was made of how regular exercise and healthy eating can improve mood. Some lucky people, although they grieve after a loss, never suffer from depression. Today’s column examines in greater depth the link between nutrition and depression, in hopes of helping some of the millions of Americans who are predisposed to depression.
Dr. Michael Greger’s book “How Not to Die” and his website nutritionfacts.org., cite studies that show that people who live a plant-based, whole (unprocessed) food lifestyle have less tension, anxiety, depression, anger, hostility and fatigue. Here are some examples:
• Removing meat, fish, poultry and eggs from the diet of depressed people improves mood scores in just two weeks.
• Diets high in unprocessed carbs and low in fat and protein decrease anxiety and depression.
• A study of a U.S. corporation showed that employees at 10 different sites noted less depression and anxiety and had increased productivity after going plant-based.
• Eating vegetables just three times a week improved depression scores by 60 percent in another study.
• Consumption of beverages with sugar (a processed substance) increased the risk of depression, as did artificial sweeteners.
Here are some of the reasons that eating plants helps prevent and treat depression:
• Arachidonic acid: Our bodies make this omega-6 fatty acid, which causes the inflammation we need to promote healing after an injury. However, high levels caused by dietary intake inflame the nervous system including the brain, which leads to depression. The two foods that are primarily responsible for high levels of arachidonic acid are poultry and eggs, although meat and fish also contribute. Arachidonic acid is not found in plants.
• Oxidative stress, which causes free radicals, plays a role in depression. Fruits and vegetables are loaded with antioxidants, particularly ones with intense flavor (herbs and spices, especially turmeric and amla) and color (e.g. greens, peppers, yams, berries). Animal products contain few to no anti-oxidants.
• Lycopenes are antioxidants found in tomatoes, watermelon, pink grapefruit, guava and papaya, and high blood levels are associated with less depression.
• Low blood levels of folate are associated with depression. Greens and beans are good dietary sources of folate. Note that folic acid supplements don’t help (natural folate isn’t exactly the same thing as folic acid in supplements, plus we evolved to get our nutrients from the food we eat, not pills).
• Monoamines include the neurotransmitters serotonin and dopamine, which help prevent depression. Monoamine oxidase (MAO) is an enzyme that breaks down excess monoamines. Depressed people have a defect in this regulatory mechanism, causing high levels of MAO, which results in low levels of the depression-preventing monoamines. Pharmaceutical companies have developed MAO inhibitors, but they can cause serious side effects. Several foods have natural, side-effect-free phyto (plant) nutrients that inhibit MAO: apples, berries, grapes, kale, onions and green tea, cloves, oregano, cinnamon and nutmeg.
• Tryptophan is a building block of serotonin, the “happiness hormone.” According to Dr. Greger, foods with a high tryptophan-to-protein ratio help facilitate tryptophan transport into the brain: sesame, sunflower, pumpkin and butternut squash seeds.
In conclusion, the same plant-based foods that are necessary for optimal physical health also cause optimal mental health. This is not surprising, because the human genome evolved over some 20 million years when pre-humans were herbivories. Also, our jaw and GI structures are those of herbivories rather than carnivores. This is not to say that all plant-based people are free of depression. But plant-based nutrition can help prevent and treat depression. And being on a plant-based diet enhances the effect of anti-depressants.
Dr. Feinsinger, who retired from Glenwood Medical Associates after 42 years as a family physician, now has a nonprofit Center For Prevention and Treatment of Disease Through Nutrition. He is available for free consultations about heart attack prevention and any other medical concerns. Call 970-379-5718 for an appointment. For questions about his columns, email him at firstname.lastname@example.org.