In this series on the link between food and mood, we will start out by talking about some of the worst offenders: the foods we should avoid for optimal mental health.
You can also watch the video version of this post on YouTube:
What exactly are the four worst foods for brain health?
Sugars are part of a larger group of macronutrients called carbohydrates.
Carbohydrates vary in complexity – some are large molecules that take a long time to break down and release their energy in the body. These are called “complex” carbohydrates. Because they release their energy only very slowly, they are like slow-burning fuel.
But simple sugars are much smaller and less complex, so they don’t take as long to break down in the body. So they tend to dump all their energy at once, like striking a match.
Some common simple sugars are sucrose (another name for table sugar) and fructose (the sugar found in fruit).
What? We are concerned with fruit sugar? Does that mean that fruit is bad?
No, not necessarily. Fructose that comes in its original package – bananas, apples, berries, etc. – is not really a concern because the packaging provides plenty of other healthful benefits like fiber, vitamins, phytochemicals, and antioxidants. Fructose that has been stripped out of fruit, however, is a simple sugar and can have some negative effects.
Simple sugars can be bad for the following reasons:
They steal nutrients from the body.
All carbohydrates require specific nutrients to be absorbed into the body: vitamins B1, B2, B3, B5, B6, and magnesium. Refined sugars are stripped of these nutrients, so they steal them from body reserves. This contributes to the general lethargy of a high-sugar diet.1
They cause sugar crashes.
Eating a cookie or candy bar dumps a ton of simple sugar into the bloodstream all at once. The body must then either use all this energy or, if it doesn’t need the energy right away, store it.
Insulin is the hormone in charge of doing this – it “knocks” on the doors of the body’s cells and says, “Hey! Sugar delivery! Do you want some?”
A large sugar dump will cause a large release of insulin. This is what causes the burst of energy or “high” you feel in the first hour after eating the cookie or candy bar. But once insulin has cleared the bloodstream (and it won’t take long with simple sugar), you will start to feel crummy – tired, listless, and depressed.
They cause longer term problems like diabetes.
Type 2 diabetes can develop when the body’s cells become “resistant” to repeated knocking by insulin.
The sugar molecules have no choice but to stay out in the bloodstream, where they start acting like a gang of no-good hooligans. They damage blood vessels and nerve cells, leading to vascular and nervous system problems. This damage can pave the way for depression.
Depression is twice as common in diabetics as in the general population.5
Studies have shown that diabetes and depression are linked in both directions: diabetes increases the risk of depression and depression increases the risk of diabetes. This probably means that the two share several biological pathways; not just blood sugar problems, but problems with inflammation as well.5
How to Stop the Sugar Cycle
When we stop feeding the sugar cycle, we stop falling into a sugar funk followed by intense cravings for more.
Alexandra Massey, author of Improve Your Mood With Food, suggests a two-pronged approach: 1) controlling intake of “hidden” sugar and 2) limiting the amount of added sugar.
1. Control our intake of “hidden” sugar.
Because sugar is a preservative, it is added to countless supermarket products that one would never suspect unless one reads the label. If sugar is one of the first three ingredients, it is a high-sugar product.
Sugar goes by many names, which can make label-reading a little more challenging. Here’s one clue: the technical name of simple sugars often ends with “-ose:”
Other common sugar ingredients:
- agave nectar
- corn syrup
2. Limit the use of added sugar.
- Replace sugary snacks with their natural counterparts (an apple or banana).
- Stop adding it to things. You and I may start out thinking that our grapefruit, cereal, or hot beverage is bland without an extra spoonful of sugar. But our palates are adjustable. So one trick is to go slowly, decreasing the amount of sugar used over time.
- Replace sugary toppings (e.g. maple syrup) with fruit toppings.
- Add nuts. Personally, I love having nut butter and honey on my breakfast pancakes. The nut butter seems to cut my need for too much sweetness. My husband uses the same trick – when he wants to stop eating dessert, he eats a few almonds or walnuts. For some reason, this signals an end to the sugar craving.
- Use spices instead of sugar, e.g. cinnamon with apples, ginger with bananas.
2. Other Refined Carbohydrates
Anything made with white flour is a refined carbohydrate. Unrefined flour is usually a shade of brown – this indicates that it still retains its fiber, healthy oils, vitamins, and minerals.
We use the Glycemic Index (GI) to assign a score to a food depending on how quickly it causes blood sugar to rise. Table sugar is given a GI of 100, and this is the standard by which all other foods are ranked.
White flour-based pasta and baked goods have a high GI – this means they release sugar into the bloodstream almost as quickly as straight table sugar.
Unrefined, whole-grain pastas and baked goods have a lower GI and therefore are a slower-burning fuel. They release sugar slowly, do not result in sugar crashes, and do not result in insulin resistance. GIs of 55 or lower are considered healthy, unrefined carbohydrates. /
There is also another measure called Glycemic Load (GL) that tells us how much sugar a particular food can deliver to the bloodstream per serving.
This is important, too, because GI and GL can give very different pictures of the same food: watermelon has a very high GI (80) because it releases sugar very quickly into the bloodstream; however, its GL is very low (5) because the amount of carbohydrates per serving is very low.
Both a high GI and a high GL diet has been linked to higher risk of depression.6
Tips for carb consumption:
- Gradually change over from refined, white flour-based products to their unrefined counterparts. I’ve mentioned before that inflammation is one contributing factor of depression; whole grains are rich in a type of fiber call beta-glucans that promotes healthy immune function.7 Whole grains also have phytochemicals that reduce the oxidative stress associated with inflammation and depression.8
- Switch to whole-grain breads from white breads
- Switch to whole-grain or legume-based pastas from white pastas
- Use brown rice in place of white rice
- Keep GL levels to 60-80 grams per day.
3. Bad Fats
There are two main types:
Trans fats do not exist in nature; they were invented by scientists to increase the shelf life of the products they are put into.
To make a trans fat, a scientist takes a liquid oil and adds hydrogen to it. In liquid oils, the fat molecules have “kinks” in them that prevent them from getting too close to each other. Adding hydrogen (also called “hydrogenation”) straightens out the kinks and makes the fat molecules lie closer together, thus transforming the liquid into a solid (think vegetable shortening).
Trans fats are found in most commercially prepared fried foods, margarines and margarine spreads.
They are also in most commercial baked goods like cakes, cookies, and pastries. Along with the high GI of these foods, their trans fat content is yet another reason why they are bad for you. Trans fats induce inflammation,9 which may be one way they contribute to depression.10
Saturated fats are found in red meat, high fat dairy, eggs, and seafood. Some plant foods are also high in saturated fats: coconut and palm oil.
Saturated fats increase the levels of cholesterol and triglycerides in the bloodstream. This is not just bad for the heart; it is also bad for the brain. Higher blood cholesterol and triglycerides has been linked to faster development of depressive symptoms.11 When cholesterol is lowered through statin drugs, depressive symptoms improve.12
Meat and eggs can also contain an “omega-6” fatty acid called Arachidonic Acid. Once in the body, arachidonic acid is rapidly converted into chemicals that cause inflammation in the brain, which has been shown clinically to lead to depression.13
How to Eliminate Bad Fats.
In recognition of trans fats’ role in heart disease, the U.S. Food and Drug Administration removed it from the list of “generally recognized as safe” foods in 2015. Food producers now have to get special permission even to include it in their commercially-produced foods.
The FDA also requires food producers to report the amount of trans and saturated fat in nutrition labels. So the easiest way to eliminate bad fats is to read labels.
Trans fats should be completely avoided if possible.
For optimal mental health, saturated fats should comprise no more than 10% of one’s daily food intake.14
Replace bad fats with good fats.
Good fats are polyunsaturated fats like:
- olive oil
- nuts and seeds
- sunflower and rapeseed oils and spreads
- vegetable oils
- oily fish
Research has shown that as polyunsaturated fat levels in the blood go up, inflammatory chemicals go down.15
I will discuss other benefits of good fats (and omega-3 fats in particular) in another post.
4. High-Fat Dairy Products
Dairy products are often high in saturated fats which increase blood cholesterol. Cholesterol does not only damage and narrow the arteries supplying blood to the heart. It also travels to the brain and narrows the arteries there, too.
Just like the heart, the brain will also suffer from the ensuing oxygen and nutrient deprivation. This is likely the reason why cholesterol has been linked to faster development of depressive symptoms,11 while cholesterol-lowering drugs improve symptoms.12
Solution: Replace dairy products with low-fat or non-animal substitutes:
|Replace this Dairy Food….||With this Substitute|
|Hard Cheese||Soy cheese (Daiya Brand is good)|
|Cream Cheese||Soy cream cheese (Try the Tofutti brand)|
|Ice Cream||Soy, coconut or cashew-based ice cream (Haagen-Dazs makes some awesome flavors. But watch the sugar intake!)|
|Milk||Soy, almond, cashew, or coconut milk (Silk is a good brand)|
|Yogurt||Soy yogurt (Silk is a good brand. But watch the sugar intake!)|
|Butter||Earth Balance spread is a good substitute|
1 Massey, A., & Bean, A. (2006). Improve Your Mood With Food. Virgin Books. p.14
2 Li, Y., Lv, M. R., Wei, Y. J., Sun, L., Zhang, J. X., Zhang, H. G., & Li, B. (2017). Dietary patterns and depression risk: a meta-analysis. Psychiatry research, 253, 373-382. (Data from 21 studies involving 117,229 participants were included in the this meta-analysis.)
3 Molendijk, M., Molero, P., Sánchez-Pedreño, F. O., Van der Does, W., & Martínez-González, M. A. (2018). Diet quality and depression risk: a systematic review and dose-response meta-analysis of prospective studies. Journal of affective disorders, 226, 346-354.
4 Popkin, B. M. (2015). Nutrition transition and the global diabetes epidemic. Current diabetes reports, 15(9), 64.
Drewnowski, A., & Popkin, B. M. (1997). The nutrition transition: new trends in the global diet. Nutrition reviews, 55(2), 31-43.
5 Moulton, C. D., Pickup, J. C., & Ismail, K. (2015). The link between depression and diabetes: the search for shared mechanisms. The Lancet Diabetes & Endocrinology, 3(6), 461-471.
6 Rahimlou, M., Morshedzadeh, N., Karimi, S., & Jafarirad, S. (2018). Association between dietary glycemic index and glycemic load with depression: a systematic review. European journal of nutrition, 1-8.
Salari-Moghaddam, A., Saneei, P., Larijani, B., & Esmaillzadeh, A. (2018). Glycemic index, glycemic load, and depression: a systematic review and meta-analysis. European journal of clinical nutrition, 1.
7 Volman, J. J., Ramakers, J. D., & Plat, J. (2008). Dietary modulation of immune function by β-glucans. Physiology & behavior, 94(2), 276-284.
8 Bilici, M., Efe, H., Köroğlu, M. A., Uydu, H. A., Bekaroğlu, M., & Değer, O. (2001). Antioxidative enzyme activities and lipid peroxidation in major depression: alterations by antidepressant treatments. Journal of affective disorders, 64(1), 43-51.
9 Iwata, N. G., Pham, M., Rizzo, N. O., Cheng, A. M., Maloney, E., & Kim, F. (2011). Trans fatty acids induce vascular inflammation and reduce vascular nitric oxide production in endothelial cells. PloS one, 6(12), e29600.
10 Sánchez-Villegas, A., Verberne, L., De Irala, J., Ruíz-Canela, M., Toledo, E., Serra-Majem, L., & Martínez-González, M. A. (2011). Dietary fat intake and the risk of depression: the SUN Project. PloS one, 6(1), e16268.
11 Beydoun, M. A., Beydoun, H. A., Dore, G. A., Fanelli-Kuczmarski, M. T., Evans, M. K., & Zonderman, A. B. (2015). Total serum cholesterol, atherogenic indices and their longitudinal association with depressive symptoms among US adults. Translational psychiatry, 5(3), e518.
12 O’Neil, A., Sanna, L., Redlich, C., Sanderson, K., Jacka, F., Williams, L. J., … & Berk, M. (2012). The impact of statins on psychological wellbeing: a systematic review and meta-analysis. BMC medicine, 10(1), 154.
13 Walther, A., Cannistraci, C. V., Simons, K., Durán, C., Gerl, M. J., Wehrli, S., & Kirschbaum, C. (2018). Lipidomics in Major Depressive Disorder. Frontiers in psychiatry, 9, 459.
14 World Health Organization: Population nutrient intake goals for preventing diet-related chronic diseases.https://www.who.int/nutrition/topics/5_population_nutrient/en/
15 Clarke, R., Shipley, M., Armitage, J., Collins, R., & Harris, W. (2008). Plasma phospholipid fatty acids and CHD in older men: Whitehall study of London civil servants. British journal of nutrition, 102(2), 279-284.
Dr. Pamela Coburn-Litvak has published research articles on exercise and stress in Neuroscience and Neurobiology of Learning and Behavior. After receiving a Ph.D. in Neurobiology and Behavior from the State University of New York at Stony Brook, she served as both Assistant Professor of Physiology & Pharmacology and Special Assistant to the Vice President for Research Affairs at Loma Linda University in Loma Linda, California. She then joined the Biology department at Andrews University and developed courses in human physiology as well as the neurobiology of mental illness. She also founded Rock @ Science LLC, a company that specializes in health and science education and web development. She co-developed the brain and body physiology segment of the Stress: Beyond Coping seminar with its creator, Dr. William “Skip” MacCarty, DMin.
Dr. Coburn-Litvak currently lives in California with her husband. Their two daughters are mostly grown and attending school elsewhere.
When she’s not studying or teaching about stress, she enjoys stress-relieving activities like puttering around the garden, taking nature walks with her family, knitting, cooking, and reading.