About twenty teaspoons of sugar a day, according to the National Health and Nutrition Examination Survey database. American men as well as teenagers of both sexes ingest, on average, 335 calories a day from soft drinks, sports/fruit drinks, candy, cakes, cookies, dairy desserts and milk products. Women consume about 363 calories a day from the sugar in these same foods.
The price for ingesting sugar calories may be high. Experts blame sugar for spurring the epidemic of hypertension, obesity, diabetes, kidney disease, and cardiovascular disease. Evidence suggests that a diet low in sugar but rich in fruits, vegetables, fiber-rich whole grains, lean meats, fish, poultry, and low-fat or fat-free dairy products can improve overall health and also stave off certain diseases.
But what’s the connection between sugar intake and mental health? Does a healthful diet improve mood and overall functioning? Do dietary factors play a role in the development of psychiatric disorders? To what extent should reducing sugar intake play a role in the management of mental health disorders? And how about better eating more generally? Do people who eat lots of fruits and vegetable feel better and stay more emotionally healthy?
Researchers have addressed few of these questions thoroughly using sophisticated double-blind studies. However, sugar plays a documented role in the development of medical problems, which, in turn, are associated with an increased likelihood of mental health difficulties. Simply put, it can be depressing to have cardiac problems or diabetes. The reverse may also be true – that individuals with mental health disorders are more likely to have a higher sugar intake given links that have been established for anxiety, depression, and substance use. Therefore, there’s a natural association between sugar intake and mental health problems.
Depression serves as a good example of the link between mood and food. People with depression often experience challenges with their weight. Some lose interest in food and lose weight, while others eat more and gain weight. Medication for depression can also affect weight. Weight loss and weight gain can lead to further mood disruptions. “Weight loss and lack of good nutrition will deprive the brain of glucose and the other nutrients that control mood,” the Mental Health Foundation says. “Putting on weight unintentionally or feeling out of control of your eating can increase your depression and can lead to yo-yo dieting, which leaves you further out of control.”
Some very popular assumptions about diet and mental health have not panned out at all. The best example is the long-held notion that sugar causes ADHD symptoms and that, in turn, the disorder can be treated through diet. Careful research has disproven that notion entirely. While sugar intake can affect a child’s behavior, the change rarely results in a level that merits a diagnosis of ADHD. Further, studies testing the impact of dietary treatments have shown little, if any, benefit. The latest victim of double-blind studies is a fatty acid called Omega 3-6. While open trials showed good results, blinded placebo trials failed to document those improvements. The bottom line: Sugar intake neither causes ADHD, nor does its reduction treat the disorder.
An area in which nutritional factors may play a meaningful role is in schizophrenia and bipolar disorder. For example, some researchers have suggested an association between high sugar intake and schizophrenia, because sugar can cause suppression of the hormone BDNF. However, those relationships or treatments based on them have not been firmly established.
It certainly can help all of us to eat a healthful diet and limit sugar intake. The links between too many calories due to high sugar intake and medical/dental problems are well documented. And, while a good diet may not be the silver bullet for treating most psychiatric problems, it surely can contribute to a healthier outcome.