08 Apr 2021
Are walnuts good for your brain?
You are what you eat
While we aren’t sure where the phrase ‘you are what you eat’ originates from, we do know that it holds some truth. There are many whole foods shaped like the body part they nourish.
Maybe the phrase should be more like ‘You nourish what you eat’.
Take a look at the shape of an avocado and what do you see? Note that avocados are a healthy source of folate that can reduce the risk of cervical dysplasia. Not only that, but an avocado takes nine months to grow!
If you guessed that an avocado looks like the uterus, that’s exactly right.
Celery stalks target bone strength, as they are a great source of silicon, and what do they look like? Our bones!
Some other foods that fit the ‘you are what you eat’ phrase include kidney beans (the hint’s in the name), which help heal and maintain kidney function. Sweet potatoes are high in beta-carotene, an antioxidant that protects all tissues in the body including the organ it’s shaped as—the pancreas.
It’s no secret that ginger is a go-to herbal supplement for stomach aches. Next time you see ginger root at the shop, notice its resemblance to the digestive organ.
The most well known food that looks like a body part is the walnut. Its shell is not only shaped like the brain with folds and wrinkles, but the seal in the middle makes the shell resemble the left and right hemispheres of the brain.
These nuts are one of the best foods for supporting brain health, so it’s no surprise that they are shaped this way.(1)
Nutritional value of walnuts
Walnuts are made up of Omega-3 fatty acids, vitamin B-6, and antioxidants such as vitamin E, flavonoids, ellagic acid, gamma tocopherol, and melatonin, all of which are linked to better brainpower.(2)
Not only that, but walnuts reduce oxidative stress and inflammation—two things that are associated with brain diseases linked with older age (think Alzheimer’s and Parkinson’s).(3)
Omega-3s and the brain
Omega-3 fatty acids are polyunsaturated fats, which play a large role in anti-inflammatory processes and the structure of cell membranes. Our bodies cannot produce Omega-3s on its own, therefore we have to get these fats from our diet.
Most nuts contain monounsaturated fats, but walnuts are superior because they are the only nuts made up of mainly polyunsaturated fat, with a portion of this fat in the form of alpha-linolenic acid (ALA).
In one ounce of walnuts, there are 2.5 grams of ALA, making them the only tree nut with such an excellent source of this essential fatty acid!(4)
ALA is the precursor to the Omega-3 fatty acids EPA and DHA, acids that have anti-inflammatory effects. While more research is needed to fully understand ALA’s role in maintaining DHA levels, early studies show evidence that ALA may be able to fulfil the human requirement for DHA in the body.
This recent find could mean that walnuts are especially useful for a vegan diet. As fatty fish is often cited as the best source for DHA, but if we can eat enough ALA from plant sources, our bodies can convert this to enough DHA to meet our requirements.(5,3)
Vitamin B-6 and the brain
Vitamin B-6 plays a crucial role in supplying oxygen to the brain. This specific B vitamin helps the body use and store energy and form haemoglobin, the protein responsible for transporting oxygen from the lungs to cells in the body.
A serving of walnuts will provide you with a hearty dose of vitamin B-6 to get your oxygen flowing.
Antioxidants and the brain
Antioxidants are key for preventing oxidative stress in the body.
Oxidative stress is caused by an imbalance of free radicals and antioxidant defence. An increased level of free radicals is toxic and can damage cells, thus affecting cell and membrane properties. Antioxidants neutralise these free radicals.
The brain is most vulnerable to oxidative stress as it consumes 20% of our body’s oxygen. For example, one type of dementia (vascular dementia) is caused by a lack of oxygen to the brain, leading dead nerve cells.(6)
Therefore it’s paramount for our brain health to consume a diet which is high in antioxidant-rich foods, like walnuts.
Not only are walnuts rich in antioxidants, their antioxidant content is superior to most other foods. A study of antioxidant contents in 1,113 different food items ranked walnuts as second!(3)
Brain diseases
As mentioned previously, long-term exposure to oxidation and inflammation have been linked to brain diseases that develop in old age. These two issues can lead to brain cell damage, and reducing memory, decision-making, and motor function.
What makes walnuts especially beneficial are the nuts’ ability to break down the protein-based plaque in the brains of people with Alzheimer’s. This plaque, called amyloid beta protein or (Aβ), can induce inflammation in the brain and increase the generation of free radicals.
The plaques build up inside the brain, disrupting how nerve cells work and communicate with each other, causing them to eventually die.
Studies show that walnuts not only provide antioxidants, but also specifically protect against oxidative stress, reducing oxidative damage to lipids (fatty acids) and proteins, and cell death induced by Aβ.
In short, a long-term diet of walnuts will help keep your brain healthy and reduce your risk of developing brain related diseases like dementia.(3)
Cognitive Benefits and research
Walnut consumption can improve your memory and brain function, and there are many studies that prove so.
One study done with rats concluded that rats who were fed walnuts in their diet had improved memory, learning skills, motor development, and anxiety-related behaviour in comparison to the rats fed a walnut-free diet.
In Spain, a human study tested cognitive behaviour in adults on a Mediterranean diet, with 30 grams mixed nuts including walnuts. Those with this diet showed better brain function and a significant improvement in memory to the controlled group.(3)
In 2015, The University of California, Los Angeles studied adults’ performance in cognitive testing and its correlation to walnut consumption.
Adults aged 20-59 years old with walnut consumption of 10.3 grams took 16.4 milliseconds less time to respond on the simple reaction time test. The study concludes that cognitive function was consistently greater in participants that consumed walnuts—regardless of age, gender, or ethnicity.(7)
Walnuts and depression
Consuming walnuts may help fight off depression and support overall mood health.
After reviewing nine years of data from the National Health and Nutrition Examination Survey (NHANES), scientists concluded that walnut consumers showed lower depression scores compared to non-nut consumers.
The factors for this study included a greater interest in doing things, less hopelessness, and more energy. Non-nut consumers were more likely to struggle with concentration, believe they were moving and speaking abnormally, and have a negative self-image.(8)
Walnuts and the Mediterranean diet
You may have heard about the Mediterranean Diet, as it has gained popularity in recent years with no signs of stopping. It’s popular for good reason, as it’s one of the best diets out there for promoting long-term health benefits.
The diet was discovered in the 1960’s when research showed that men from the Mediterranean regions (Crete, Greece, and Italy) had lower rates of heart attacks. This sparked an investigation on whether or not their traditional Mediterranean diet played a part in their overall health.
The Mediterranean diet consists of eating meals with an abundance of vegetables and fruits, whole grains, oils, and fish, and less red and processed meats, and dairy.
Can you guess what food is a staple in this diet? Oh yes, it’s walnuts!
Brain health and the Mediterranean diet
Studies suggest that adopting the Mediterranean diet can slow cognitive decline and lower the risk of developing Alzheimer disease.(9)
The Alzheimer’s Society notes that adhering to this diet may also slow the rate of decline in memory and thinking.(10)
The Mediterranean diet could even correlate with lower depression risk, studies show.
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