Is there a link between diet and depressive disorders? We spoke to a clinical nutritionist to get some insight.

“Poor diet won’t cause major depressive disorders, but it can exacerbate them,” says clinical nutritionist Adele Pelteret.

“There’s a clear link between depression and diet. I believe mild forms of depression can even be caused by poor diet. There are a variety of foods that influence brain behaviour. Brain chemicals, or neurotransmitters, which regulate mood and behaviour, are controlled by what we eat and how much we absorb of what we eat,” she says.

Low glycaemic index (GI) foods are best. These release sugars into the blood stream slowly and help maintain the correct level of energy. Sugary or over-processed and refined foods can result in too much sugar being released into the system. This causes the blood sugar level to rise very quickly.

“The pancreas then releases insulin and the liver releases GTF (Glucose Tolerance Factor), which brings the blood sugar level down quickly. But because it happens so quickly, it goes too low, making you feel tired, unable to concentrate and often unhappy.

“You then crave some form of stimulant or sugary food or refined carbohydrates to make your blood sugar levels rise again.”

Sugar highs and lows

She says if you’re eating badly, these peaks and troughs continue daily, creating a cycle that leaves you feeling lower and lower. Teens dealing with these blood sugar highs and lows may resort to drugs, or the socially acceptable ‘drugs’ like caffeine, chocolate, nicotine and alcohol, to give them the short-lived ‘upper’ feeling from a rise in blood sugar level, she says.

Caffeinated or cola-based drinks with sugar in them, are particularly problematic. Caffeine and other stimulants in drinks produce a stress reaction in the body that depletes or neutralises B vitamins, essential for good brain function. Sugary foods also cause the brain to over or under produce serotonin and norepinephrine, the two neurotransmitters most commonly implicated in depression.

“This is also why one of the risk factors for depressive disorders is diabetes. When you are depressed, the best thing you can do nutrition-wise is to balance your blood sugar levels and keep them constant. Eat complex carbohydrates that turn to sugar more slowly in the system. Ensure you’re getting enough omega-3 fatty acids and B vitamins that are essential for brain function,” says Pelteret.

“Eat fresh fruit [diabetics should be cautious about fruits high in glucose; consult a doctor if need be]. Consumer vegetables, nuts, seeds, legumes and whole grains. Check for food allergies or intolerances as well as for chemical toxicity (particularly heavy metal toxicity). These almost always play a factor in behavioural and affective/mood disorders.”

Sarah Young