While many researchers spend time debating whether depression leads to poor diet or poor diet leads to depression, the link between the two has become evident. Poor diet can exacerbate depression and the question of whether it is a primary cause is moot: changes in diet can alleviate depression.
So what is the “depression diet”? Processed and refined foods, fast foods, sugary foods, large amounts of simple carbohydrates, caffeine and alcohol all lead to depression.
A recent University of London study, led by Dr. Eric Brunner, followed the eating habits of 3,486 adults for 5 years. The study revealed that those who ate diets high in processed and fast foods were almost 60% more likely to suffer from depression.
This type of western diet, which is spreading rapidly over the globe, is also marked by low intakes of essential fatty acids and amino acids and reduced amounts of vitamins and minerals in their natural state.
Another UK report, produced by the organizations Sustain and the Mental Health Foundation, gives credence to the idea that dietary changes over the last century (industrial farming, the use of pesticides and herbicides, the degradation of nutrients from high-volume planting and transport of food over long distances) is a primary force behind global epidemic mental health issues.
Our bodies are interconnected systems and everything we put in them, expose them to or do to them affects the whole person, not just one area. The foods we eat not only affect our digestion and energy, but also affect the neurochemistry of our brains, specifically—neurotransmitters. Brunner explains, “If your diet is high in foods that make blood sugar levels go up and down like a yo-yo, then it’s not good for your blood vessels and is bound to have an effect on the brain.”
The neurotransmitters dopamine, norepinephrine and serotonin affect mood and behavior. Serotonin eases tension and dopamine and norepinephrine raise alertness.
Complex carbohydrates increase serotonin levels and high protein foods increase the production of dopamine and norepinephrine.
The high levels of omega-6 and 9 fatty acids in refined and processed foods have been found to cause dramatic problems in the production of serotonin. These alterations in serotonin levels can be passed to a fetus through the diet of the mother and there may be some evidence that they permanently alter the brain in children and adolescents. A study of 38 industrialized countries found that the rates of murder and ingestion of unhealthy oils are strongly correlated.
Synthetic fats have been found to block the absorption of fat. Unfortunately, they also block our ability to utilize fat-soluble vitamins and minerals.
Michael Murray, author of Natural Alternatives to Prozac, believes hypoglycemia is an overlooked commonality in depression. Consuming sugar and simple carbohydrates such as white rice, white bread and white flour causes a rapid and dramatic rise in blood sugar, which produces an exaggerated insulin response. Then, because simple sugars are broken down so rapidly, low blood sugar level results: hypoglycemia.
Murray writes, “Hypoglycemia (low blood sugar) is another common cause of depression…The association between hypoglycemia and depression is largely ignored by most physicians—they simply never even consider it as a possibility despite the fact that several studies have shown hypoglycemia to be very common in depressed individuals.”
Sugar is addictive and the sudden rush that it gives leads to cravings for more, bumping the body’s appetite for real nutrition off the shelf.
Sugar and its unnatural cousin—high fructose corn syrup—are present in a huge variety of processed foods today. Among the foods that are sugar-free, aspartame is commonly used. Although many industry-funded studies claim that aspartame is not harmful, independent studies find facts to the contrary.
Aspartame is mainly composed of aspartic acid, phenylalanine and methanol. Methanol is a type of alcohol that is extremely poisonous and is broken down by the body into toxic compounds formic acid and formaldehyde. Phenylalanine is an amino acid that affects many neurotransmitters and is associated with cancer.
Aspartic acid is an amino acid that excites neurons and has been linked to anxiety, depression and headaches.
Even casual drinking can increase the effects of depression. Alcohol lowers serotonin and norepinephrine levels. It depresses the brain and nervous system and blunts the action of stress hormones. When people who had just one drink per day abstained for 3 months, they experienced improvements in mood.
Alcohol undermines physical and mental health in other ways too. Andrew Weil says that alcohol speeds up the breakdown and elimination of valuable antioxidants from the body, especially folate, low levels of which have been linked to increased incidence of depression.
As alcohol impairs judgment and decreases inhibition, it becomes more common for thought of suicide to become real actions. Alcohol affects all decision-making, including getting help for depression.
This stimulant can lead to overstimulation of the nervous system and can increase the incidence of anxiety and insomnia, both linked to depression. Caffeine dampens the body’s appetite and slows absorption of nutrients.
Food colorings and preservatives have been linked to many cancers, the proliferation of free radicals, damage to nerve cells, ADD and ADHD and increased anxiety and mood disorders. Many of the food additives commonly used in U.S. food products have been banned in several other countries.
Recent research has linked low levels of vitamin D with cardiovascular disease and depression. Vitamin D supplementation has helped those suffering from seasonal affective disorder (SAD).