Beating depression with diet
Having a steady supply of B vitamins can help low mood through their role in supporting the nervous system. Vitamin D has also been seen to help boost mood, although not proven yet by studies, many depressed people have low vitamin D levels. Levels of Vitamin D deficiency in Britain are the highest in 50 years, with one in five of us suffering severe deficiency. It is linked to an increased risk of heart disease, bowel cancer, multiple sclerosis and diabetes.
Government guidelines now recommend that from October to March we take a Vitamin D supplement.
Beating the blues: Essential Foods
Serotonin is the so called 'happiness' hormone - a neurotransmitter or chemical messenger that plays an important role in both our brain and digestive system. Indeed, although some serotonin is made in our brain, around 90% of it is found in our gut. Quite the multi-tasker, it also contributes to the functioning of our cardiovascular system, the formation of bones and the contraction of muscles, all of which can indirectly boost our mental health by improving our physical health.
Healthy Fats:
- Herring, mackerel, fresh tuna, salmon, anchovies, sardines, trout, walnuts, flaxseed, hempseed oil, chia seeds, broccoli, kale and cauliflower.
Serotonin and tryptophan-rich foods:
- Serotonin - Walnuts, bananas, plums, kiwis, tomatoes
- Tryptophan - Turkey, tuna, natural yoghurt, oats, potatoes, sunflower seeds, and butternut squash seeds
B Vitamins:
- Eggs, beans, pulses, lentils, mushrooms, quinoa, oats, brown rice, marmite.
Vitamin D:
- Mushrooms, oily fish, red meat, egg yolks, fortified cereals.
Serotonin - the 'happiness' hormone
Healthy fats and omega - 3.
Possible Digestive aids:
- Rocket, watercress, lemon, ginger, cayenne pepper, organic apple cider vinegar, dandelion tea, mint tea, fennel tea
Zinc:
- Sunflower seeds, pumpkin seeds, salmon, scallops, poultry and squid
(Source: The Happy Kitchen - By Rachel Kelly)
The serotonin in our gut helps with a number of important digestive functions, in particular the gut's natural movements that break up and digest food and ensure we have regular daily motions.
Research suggests that serotonin levels may be linked to some gastrointestinal symptoms, including constipation, diarrhoea and conditions such as irritable bowel syndrome. Given the potential links between the health of our digestive system and the mind, it makes sense to ensure our gut has the right balance of serotonin.
How can what we eat affect our serotonin levels? A few foods actually contain serotonin, albeit in low levels. These include walnuts, bananas, kiwis, plums and tomatoes. Far more numerous, however, are the foods that can increase levels of tryptophan, the amino acid from which serotonin is made and which itself is important to brain function. There is some evidence to suggest that low levels of tryptophan may play a role in depression. Studies have shown that if you feed animals meals containing all of the essential amino acids except tryptophan, their serotonin levels become depleted.
Tryptophan is found predominantly in protein-rich foods like turkey, tuna and natural yoghurt, and also in oats, potatoes, sesame seeds, butternut squash seeds, sunflower seeds and pumpkin seeds.
Vitamin B and Vitamin D
Zinc helps us with many functions, including making new cells and enzymes, and plays a role in the central nervous system. It is also thought to help brain cells communicate through neural pathways, a process known as 'neuronal plasticity', and heighten concentration. Zinc imbalances have been identified as contributors to a wide range of brain diseases, from Alzheimers's to depression. The element is found in high concentrations in the hippocampus. The hippocampus regulates emotions, maintains the brain's protective barrier and modulates aspects of our stress response system, so it is no surprise that zinc deficiency could be linked to depression and reduced focus.
Serotonin and the gut
Zinc
Protein:
- Meat, fish, eggs, chickpeas, nuts, seeds, cottage cheese, tofu, tempeh, miso, beans, lentils, brown rice and hemp protein powder
The serotonin in our brain helps to relay messages from one area of it to another. Serotonin directly or indirectly influences many of our 40 million-odd brain cells. These include the ones related to happiness, sexual desire and sleep, or, as one neuroscientist put it, all the things that are worth living for!
Some studies show that people who suffer recurrent and serious depression have depleted serotonin levels. This is why they are prescribed antidepressant drugs known as selective serotonin reuptake inhibitors (SSRIs), which are thought to work by increasing serotonin supplies in the brain.
Today, however, scientists are less certain about how exactly these antidepressants work and few believe their effectiveness is wholly linked to their serotonin-boosting properties. Other neurotransmitters such as noradrenaline can also be involved.
Setting aside how antidepressants may or may not work, we need to address the question of how else to support our brain's supply of serotonin through diet. I'm afraid this is tricky and scientists still aren't really sure of the exact answer. Every drop of blood is filtered before it is allowed to flow through the blood-brain barrier - the security system the brain has for keeping out foreign substances. Serotonin that has been created in the digestive system isn't able to travel across the blood-brain barrier.
However, while pure serotonin is turned away at our brain's gate, tryptophan is not. You might now think, 'Ah! so if I eat more tryptophan, I will boost my brain's supply of serotonin' Unfortunately the answer is once again more complicated. It turns out that the other amino acids from protein-rich foods mentioned above compete with the tryptophan to enter the brain. Our poor old brains can't cope with all the competing amino acids knocking on the door, and don't let the tryptophan in.
So what can we do? There is some limited evidence that eating carbohydrates may help facilitate the transport into the brain of tryptophan. But we need much more research before we can simply say a carbohydrate rich diet improves depression. Apart from anything else, eating too much refined carbohydrate can lead to diabetes, which in itself can cause depression!
Snacking on foods that have a high proportion of tryptophan compared to other amino acids may be the answer, especially seeds such as sesame and pumpkin. One small study found that those who ate butternut squash seeds experienced reduced social anxiety disorder.
Scientists also think there may be a link between reduced serotonin levels and low levels of vitamin D and omega-3 fatty acid. This in turn might lead to an increased risk of neuropsychiatric disorders and depression.
Given how hard it is to use diet to affect the serotonin in our brain, we need to find other ways to do it. Research has shown that both sunshine and exercise may boost serotonin production and its release.
Healthy fats, in particular, omega-3, is crucial in improving our mood. There are two main types, both of which we have to get from our diets: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA makes neurotransmitters, enabling them to be detected by our cell membranes, whereas DHA is an important part of the cell-building process. Both work to reduce inflammatory reactions. And combined evidence from a number of recent studies found that, in general, omega-3s were effective in improving depressive symptoms in both patients diagnosed with depression and depressed patients with undiagnosed depression.
Serotonin and the brain