- A new BBC show explores how junk food affects mental health with sugar
- Protein is also vital for our mood due to how it helps produce dopamine
- Here, medical nutritionist Dr Sarah Brewer breaks down the findings for global readers, and gives her take on how to make a diet that feeds your brain
You really are what you eat – and your brain health and mood are no exception.
That was the overwhelming verdict of experts looking at how food affects our mental health in the latest episode of the BBC series Trust Me I’m a Doctor.
The show, which airs on Wednesday night, explores in detail the impact of food on the brain.
The findings are fascinating – and reveal just how crucial a healthy diet is to feeling happy.
For example:
- Junk food really can affect our mental health by causing blood sugar highs and lows. This interferes with brain chemicals that affect mood.
- Protein is vital to make serotonin and dopamine – which are key to our mental health
- There are crucial nutrients that our brain requires in tiny amounts that can really affect our mental state.
- They include B vitamins, iron, calcium, magnesium, chromium, zinc and selenium.
But how exactly does each of these so-called trace nutrients affect the brain and our mood?
What are the best food sources and how much of them do you need for maximum brain function?
Below, I look at each one – B vitamins, iron, calcium, magnesium, chromium, zinc and selenium – and give the definitive answer…
Dr Sarah Brewer gives her take on how to make a diet that feeds your brain
WHY JUNK FOOD IS NOT YOUR FRIEND
When you feel tired, do you reach for a sweet snack? And when you’re upset, do you find solace in chocolate, ice-cream or a bag of chips?
Research confirms that you are more likely to turn to junk food when you’re in a bad mood, as their high fat and sugar content activates pleasure centres in the brain, triggering the release of ‘feel-good’ neurotransmitters such as dopamine and serotonin.
But there’s a catch. Self-medicating with junk food also leads to blood sugar highs and lows that interfere with how these brain chemicals function to regulate mood. The overall effect can worsen your mental health.
Avoiding quick-fix, unhealthy snacks and selecting healthy foods instead can help you overcome mood swings by providing the nutrients your brain needs in tiny amounts to maintain normal mood.
WHY B VITAMINS ARE GOOD FOR YOU
BRAIN BENEFIT: B group vitamins are involved in energy production in cells, including brain cells. They reduce tiredness and fatigue, improve nervous system function, aid memory, psychological function and cognition – the ability to think straight.
Being stressed, drinking alcohol or eating sugary foods can all deplete our level of B vitamins. And a lack of B vitamins also leads to anxiety and irritability, making symptoms worse.
Researchers have found that women with low levels of vitamin B1 (thiamin), for example, are more likely to feel less composed, less confident and more depressed than those with higher levels.
When they increased their intake of foods rich in vitamin B1, they reported a marked improvement in mood and self-confidence as their thiamin levels increased.
Other studies show that correcting low levels of vitamin B2 (riboflavin), vitamin B6 (pyridoxine) and vitamin B12 has beneficial effects on well-being, self-confidence and mood.
The B vitamins in milk help reduce tiredness and fatigue, improve nervous system function, aid memory, psychological function and cognition
RECOMMENDED DAILY DOSE:
1mg a day for men, 0.8mg a day for women
BEST FOOD SOURCES:
Yeast extracts: Whether you love it or hate it, Marmite is an excellent source of B vitamins. Each 4g serving provides between a fifth and a half of your B1, B2, folic acid and B12 needs. Although its often criticised for its salt content, a single serving provides an acceptable 0.4g salt.
Milk is an excellent source of riboflavin and provides 0.2mg vitamin B2 per 100ml, (half a small glass of milk of milk) plus 0.4mcg vitamin B12. Live yoghurt is especially good as it provides probiotic bacteria which were recently found to interact with serotonin receptors in the gut to improve mood – and may even influence food choices.
Oily fish such as salmon are often referred to as brain food due to their high level of omega-3, but they are also good sources of B vitamins, including B6 and B12 plus protein, which provides the raw materials to make brain chemicals. Try to eat fish at least twice a week, of which at least once is oily.
Turkey is a rich source of vitamin B3, with a typical turkey burger providing 4mg. The poultry also provides amino acids such as tryptophan and tyrosine which are needed to make brain chemicals such as serotonin and dopamine.
Brown rice: A serving of 100g (1/2 a small bowl) cooked brown, long-grain rice gives you thiamin, niacin and vitamin B6. By providing wholegrain fibre, brown rice also helps to maintain more even glucose levels.
Alternatively, supplement with a vitamin B complex, such as Healthspan Vitamin B Complex, which contains 8 essential B vitamins including B1,2,12.
WHY IRON IS GOOD FOR YOU
BRAIN BENEFIT: Iron is needed to transport oxygen to the brain, needed by enzymes involved in neurotransmitter metabolism – and is also needed for the production and function of brain chemicals (neurotransmitters).
Lack of iron leads to anaemia, impairs your ability to think straight and leads to low mood and depression. Lack of iron is the most common deficiency worldwide and the National Diet and Nutrition Survey (NDNS) data shows that 27 per cent of women, and as many as 48 per cent of teenage girls get less iron than is needed to prevent these deficiency symptoms.
RECOMMENDED DAILY DOSE:
8.7mg a day for men (19-64 years)
14.8mg a day for women (19-50 years)
8.7mg a day for women (50-64 years)
BEST FOOD SOURCES:
TIP: A 100g (3.5oz) serving is roughly a deck of cards in palm in your hand e.g. a standard chicken breast is around 125g
Pigs’ liver: a 100g serving of fried liver provides 17mg iron.
Black pudding: not surprisingly, as it’s made from blood, black pudding provides over 12g iron per 100g.
Red meat provides the haem form of iron which is absorbed two or three times more efficiently than the non-haem iron – the type found in plant foods.
Lack of iron impairs your ability to think straight and leads to low mood and depression. Get a dose from black pudding
Venison provides the most, at around 5mg per 100g; a grilled rump steak provides 3.6mg iron per 100g and roast duck 2.7mg per 100g. Eating 5-a-week servings of meat should ‘meet’ your iron needs.
Seafood: Cockles provide an astonishing 28g iron per 100g of flesh, but are definitely an acquired taste! Mussels are more commonly eaten and provide just under 7mg iron per 100g. Tuna canned in oil provides a mere 1.6mg iron per 100g.
Tahini paste (made from ground sesame seeds) provides over 10mg iron per 100g (around 3 heaped tablespoons) making it – along with other nuts (especially cashews) and seeds – a great healthy snack
WHY CALCIUM IS GOOD FOR YOU
BRAIN BENEFIT: Calcium is needed for electrical messages to pass along nerves, and for the release of hormones and brain neurotransmitters involved in passing messages from one brain cell to another, to maintain normal mood.
Data shows that around 6 per cent of adults and 15 per cent of teenagers get less calcium than the benchmark needed to prevent deficiency symptoms which can include increased feelings of stress and anxiety.
RECOMMENDED DAILY DOSE:
Adults (19-64 years) need 700mg of calcium a day.
BEST FOOD SOURCES
Dairy products are an important source of calcium – a pint of milk provides as much as 720mg calcium, in the readily absorbed form of calcium lactate. Milk also contains calming peptides and a glass of warm milk before bed is a well-known remedy for anxiety and insomnia.
Green veg: Kale provides as much as 135mg calcium per 100g. Broccoli is a source of calcium that that the body can absorb.
Interestingly, cooked broccoli provides 40mg calcium per 100g of which around 61 per cent is absorbable, compared with only 32 per cent of the calcium in milk although the reason is not fully understood.
Broccoli is filled with calcium which can prevent feelings of stress and anxiety
Chia seeds are rich in calcium with just 1oz (28g) – or three 3 tablespoons – providing an impressive 177mg calcium. They are also a good source of fibre, which helps to stabilise blood sugar levels.
Soy beans are an excellent source of calcium, especially tofu which is prepared with calcium and magnesium salts. Tofu can provide as much as 200mg calcium per 100g.
Sardines provide as much as 382mg calcium per small 100g tin – but only if you eat the small ‘bones’ they contain.
WHY CHROMIUM IS GOOD FOR YOU
BRAIN BENEFIT: Chromium is needed for normal energy metabolism and to maintain normal blood sugar levels. It also increases the number and activation of insulin receptors, so that more insulin can bind to cells to improve insulin sensitivity and optimise the uptake of glucose from the blood stream into cells. Lack of chromium can lead to hunger pangs, cravings and mood changes such as nervousness, irritability, confusion and depression.
RECOMMENDED DAILY DOSE:
Around 25mcg of chromium a day should be enough for adults. But the EU RDA for chromium is 40mcg
BEST FOOD SOURCES:
Mussels provide 128 mcg chromium per 100g serving
Brazil nuts provide the chromium per 100g – about four servings but bear in mind calorie content high. Brazil nuts provide around 10mcg chromium each, so four makes a great snack.
One pear contains more than your daily dose of chromium. Lack of chromium can lead to hunger pangs, cravings and mood changes such as nervousness, irritability, confusion and depression
Dried dates provide 29 mcg chromium /100g – about four servings of 25g is around 7mcg chromium per date so a good size handful of dates.
Pears provide 27 mcg chromium per 100g – works out about one pear so eating one eating a nice juicy pear will more than meet your daily need.
WHY ZINC IS GOOD FOR YOU
Without zinc, brain cells cannot respond to hormones and neurotransmitters properly – so much so that severe deficiency can suppress the production of brain hormones needed to trigger puberty and normal sexual responses. Deficiency symptoms can include loss of smell and taste sensation as well as loss of sex drive.
RECOMMENDED DAILY DOSE:
9.5mg a day for men; 7mg a day for women
BEST FOOD SOURCES:
** TIP: A 100g serving is roughly a deck of cards in palm in your hand e.g. a standard chicken breast is around 125g
Oysters provide an average of 45mg zinc per 100g
Calves’ liver contains 16mg zinc per 100g
Lean beef provides around 10mg zinc per 100g
Quorn (a mycoprotein obtained from a microfungus) provides 6.75mg zinc per 100g.
Two tablespoons (25g) of pumpkin seeds provide around 2.5mg zinc and are also a good source of tryptophan, the amino acid needed to make serotonin, a neurotransmitter which reduces anxiety and helps regulate mood
Oysters are full of zinc, which we need to prevent loss of smell and taste sensation as well as loss of sex drive
WHY SELENIUM IS GOOD FOR YOU
Selenium forms a key part of powerful antioxidant enzymes that protect brain cells from oxidative stress. It also appears to protect against cognitive decline and dementia, as well as reducing the risk of stroke. In the UK, data shows that 36 per cent of adults, and 33 per cent of teenagers get less selenium than the lower benchmark needed to prevent deficiency symptoms, which include reduced immunity and may increase the long-term risk of dementia.
RECOMMENDED DAILY DOSE:
0.075mg a day for men; 0.06mg a day for women [75 mcg; 60 mcg]
BEST FOOD SOURCES:
Brazil nuts are the best selenium source in the diet – assuming they are harvested from trees growing in selenium-rich soils, and can provide around 250mcg selenium per 100g. A single Brazil nut supplies between 50mcg and 300mcg selenium depending on the selenium content of the soil in which the tree grows. Eating one or two Brazil nuts can therefore provide your daily needs.
Cashew nuts provide 34 mcg per 100g, but other nuts contain significantly fewer amounts.
Selenium, which is found in cashnew nuts, appears to protect against cognitive decline and dementia, as well as reducing the risk of stroke
Seafood: Mussels provide 104mcg selenium per 100g; Crab can provide as much as 84 mcg selenium per 100g; lobster, prawns and squid are also excellent sources.
Sunflower seeds are an increasingly popular snack. Try sprinkling them on salads, vegetables. They are a good source of selenium and thiamin. Again, 2 servings will give you 25mg
Mushrooms can provide 9mcg selenium per 100g.
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