Best way to get your omega-3

OMEGA-3 fatty acids are essential for brain health, so you should try to eat more foods that contain them.

While oily fish is a good source, farmed fish or large species (such as tuna, halibut, mackerel, marlin and sea bass) can contain traces of mercury, which may be toxic to the brain.

We therefore recommend that you limit your consumption of fish to smaller or less contaminated varieties, such as anchovies, sardines and salmon.

You can also find omega-3 fats in walnuts, linseeds, chia seeds and hemp seeds, and green leafy vegetables such as kale, Brussels sprouts and spinach.

However, the short-chain omega-3 fats in nuts, seeds and greens are less easily absorbed by the body than the long-chain acids found in fish, so the best source of highly absorbable, toxin and pollutantfree omega-3s is marine algae — or seaweed. Try crumbling sheets of nori (which are used to make sushi and are available in large supermarkets) into your soups and stews, or look out for samphire when it’s in season during the summer.

One trial showed that omega-3 fats improved cognitive function and maintained brain structure among healthy older adults.

You could also look for a high-quality algal supplement — try Healthspan Veg-Omega 3, which uses a natural algal source (£17.95 for 60 capsules, healthspan.co.uk).