The Great Fat Debate: which fats are best for brain health?

There is a lot of confusion that exists around fats and whether they are good or bad for us. For many years fat has been villainised, but as it turns out, a fat free diet isn’t all that great for our health.

So what’s the deal?

The thing is our bodies need fat. Fat help us to absorb all of the beneficial fat-soluble vitamins from our food. Without fat, vitamins ADE and K cannot be absorbed. Some of our hormones, like oestrogen and testosterone, are made of fat. The cell walls of every cell in our body are made from fat and our nerve cells are covered in a layer of fat, known as the myelin sheath, which is needed to conduct nerve impulses. Our brains are mostly fat and so fat is especially important for brain function. Fat can stimulate the growth of new brain cells, have a positive impact on mood and improve memory too.

However, not all fats are equal. There are many different types of fat and each has its own distinct effects on the body and brain. Some fats promote brain function, while others can wreak havoc on your brain and on your hormones, especially when consumed in excess. The latest evidence suggests that the type, rather than the overall amount of fat in the diet, is key when it comes to assessing health risks.

So rather than cutting out fats completely, let’s be more selective with them so that we can have all the benefits of healthy fats while minimising the disadvantages of the less healthy ones. How do we choose the right fats? Well do the fats you’re eating come primarily from plant foods or from animal sources? If its animal sources, is it from fatty fish like salmon, or is it from fried bacon? Does it come from fresh homemade food or does it come in a box?

Fat is either saturated (as in butter, meat, dairy, and certain oils like coconut oil) or its unsaturated. Saturated fats are usually solid at room temperature and are far less likely to be damaged during cooking, which is why they have long been used in cake recipes. Unsaturated fats are typically liquid at room temperature and can be monounsaturated, as in olives and avocados, or polyunsaturated, as in fatty fish, and various nuts and seeds.

Trans fats

Then there’s another type of fat known as trans-fat. Trans fats are well and truly on the completely avoid list. Most are produced by adding hydrogen to unsaturated fats to create a product that functions similarly to a saturated fat. They are added, for example, to margarine and other heavily processed spreads. Although small amounts of trans fats do occur naturally in dairy and other animal foods, these are many found in processed foods. Artificial trans fats are linked to inflammation and can increase the risk of things like dementia, heart disease, obesity and diabetes.  One of the single most important things you can do to sustain your health and wellbeing is not to eat processed convenience foods which typically contain the wrong types of fats.

Saturated fats

When it comes to saturated fats, they are best consumed in moderation, and as a rule of thumb, plant sources are better than animal sources. In the West, we still eat too much saturated fat and should be trying to reduce this amount. Whilst not as harmful as trans fats, too much saturated fat can negatively impact overall health. Animal sources of saturated fat, such as red meat, dairy and butter can be problematic if consumed in excess. The best way to cut down on these foods is to replace them with fish, beans, nuts and oils.

Sources of vegetable fats are important too. You want to say no to refined vegetable oils like margarine which is a pro-inflammatory processed food. Some widely used oils, like sunflower, safflower, and canola oil can also be pro-inflammatory. You want to limit these. Instead focus on cold pressed, unrefined or extra virgin vegetable oils like olive oil and flaxseed oil, and more sparingly on avocado and coconut oils as well.

Polyunsaturated fats

Of the unsaturated fats, polyunsaturated fats are particularly good for your brain. A diet which is poor in polyunsaturated fats, increases the speed at which the brain ages, while a diet which is rich in polyunsaturated fats protects our brain cells over the long term. Studies have shown that people who consume at least 2 grams of polyunsaturated fat a day have up to a 70 per cent lower risk of developing Alzheimer’s Disease than those who eat less.

Polyunsaturated fats come in different varieties, the most common being omega-3 and omega-6. While the brain needs both of these fats, omega-3s are anti-inflammatory, whereas omega-6s are more pro-inflammatory. A ratio of about 2:1 or twice the amount of omega-6 to the amount of omega-3 is a good balance to aim for. However, the typical Western diet contains 20 to 30 times more omega-6 than omega-3. Ultimately, we need to be really looking at increasing our omega-3 fats, which are found in less commonly consumed foods.

As well as having anti-inflammatory properties, omega-3s help to keep our moods steady and calm. Low levels of omega-3 are linked with an increased risk of depression. So, by restricting these essential fatty acids from our diets, in an effort to lose weight for example, we may be inadvertently increasing depressive symptoms. 

So where can we find these omega-3s? Fatty fish like salmon, mackerel, trout, herring, anchovies and sardines are the best natural sources of omega-3s. If you want to give your brain a boost, try to include 2 portions of fatty fish in your diet every week.

If you are vegan or vegetarian, and fatty fish isn’t an option for you, flaxseeds and chia seeds are good alternatives, as are walnuts, olives, olive oil, almonds, and soybeans. A good way to include more ground flax and chia seeds is to sprinkle them on top of soups and salads. Keep in mind that omega-3s in plant-based foods are in a weaker form than those found in fish, so you will need to eat more of them to obtain the same benefits.

Although fish has many health benefits, some larger fish such as swordfish, shark and most types of tuna, contain high levels of mercury which is a neurotoxin. So, you don’t want to eat these more than a few times a month. Luckily, the lowest levels of mercury are found in smaller fish which fatty fish tend to be so it’s safe to have these a couple of times a week.  

Monounsaturated fats

In addition to eating plenty of omega-3s, a higher intake of monounsaturated fats is also associated with better cognitive performance. So where do we find this type of fat? Well foods high in monounsaturated fat include nuts such as almonds, cashews, hazelnuts, pistachios and brazil nuts.

Now the trick with nuts is to buy them with their peel still on, or even better, still inside their shell. Not only does this protect these delicate foods from light and heat, keeping them from turning rancid, but it preserves their nutrients and makes them taste better too. Try to avoid buying blanched, flavoured, salted or seasoned nuts as these then fall into the processed foods category.

When it comes to fats, you needn’t fear them. They are essential for our health and wellbeing so try to have between 3 and 5 portions of healthy fats a day. Maximising your intake of polyunsaturated fats whilst minimising trans fats is an excellent first step toward optimal fat consumption.