Did you know that the different types of dietary fats you eat can impact your mood? 

After the low-fat diet craze that peaked in the 80’s and 90’s, it’s no wonder that many people are still confused today about what to believe about dietary fats and health.

When it comes to eating healthy for your brain and mental well-being, a low-fat diet is not a good idea. Sure, there may be a few exceptions for people with certain medical conditions that need more specific instructions. But for most of us, it’s time to get to know your fats and make friends with dietary fats.

Not just any dietary fats. Certain types of fats, such as monounsaturated and polyunsaturated fatty acids that is. You may’ve heard of these in their abbreviated names, referred to as MUFAs and PUFAs. We’ll come back to these soon.

Being overly restrictive of dietary fats can have devastating consequences. For some, this avoidance of fats – or striving for very low caloric intakes – may negatively affect the mood and mental health in different ways.

Can a low-fat diet promote depression? 

Researchers in France investigated the effects of different dietary patterns on mental health over the course of over ten years.¹ This approach is unique compared to most other nutrition studies that typically investigate the effects of individual foods or nutrients.

A common theme that I often try to emphasize in my teachings, it’s all about the pattern! We need to move beyond the reductionist and limiting notions of what renowned author and journalist, Michael Pollan refers to as “nutritionism”.

This French study included over 12,000 people and investigated the dietary patterns and the subsequent outcomes of depression over the following years. Compared to those consuming a healthy diet, there were four different patterns of diets more likely to result in symptoms of depression.

Patterns found to be significantly associated with symptoms of depression include:

• Western diet (aka Standard American Diet, “SAD”)
• Low-fat diet (choosing fat-free meals, no-fat, low-fat dairy, etc.)
• High-snacking pattern (a lot of processed snack foods)
• High fat-sweet diet (e.g. donuts, cakes, pies, and other dessert foods)

That’s not it! This study also found those who ate the healthiest dietary pattern had significantly less symptoms of depression. This healthy pattern was marked by higher intakes of vegetables, fruits, and fish.

What might otherwise be referred to as more traditional dietary patterns among the people included in the study. It’s not all about the healthy fats, this is just one important component of a healthful diet.

Are you concerned that dietary fat makes you fat?

Sure, this is possible. Simply put, eating too much of any calories – whether from carbohydrates, protein, or fats – can lead to weight gain. However, dietary fat, when eaten in normal amounts, does not make you gain weight.

So, for good brain health, make dietary fats your friend and don’t neglect this group of macronutrients in your balanced diet.

Just be more particular about which foods your dietary fats are coming from.

Dietary fats have many important roles we can’t afford to overlook

A few of the important roles of essential fatty acids (MUFAs/PUFAs):

• Major source of energy in the diet
• Helps absorb certain nutrients (vitamins A, D, E, and K)
• Needed to build cell membranes (outer protective layer of cells)
• Essential for blood clotting
• Hormonal balance

It’s not just the amount, it’s the type that matters!

Some of the healthiest dietary patterns have a few things in common when it comes to fats. Consider the Mediterranean Diet, the anti-inflammatory diet, or the DASH eating plan, just to name a few. These are some of my favorite healthful dietary models to look at.

All of these healthful dietary patterns emphasize getting fats primarily from foods rich in monounsaturated fats (MUFAs) and one particular type of polyunsaturated fats (PUFAs), omega-3 fatty acids.  They also limit foods that are high in saturated fats and trans fats. This contrasts greatly from the Standard American Diet.

The essential fats (required for good health) include monounsaturated fats and polyunsaturated fats. The other two types of fats not considered essential for health are saturated fats and trans fats (aka hydrogenated oils).

Furthermore, many Americans tend to eat plenty of omega-6 PUFAs in the form of highly refined oils. Although many of these processed oils are very high in polyunsaturated fats, there’s one more important note here.

It’s one particular type of PUFAs, omega-3’s, that have anti-inflammatory effects. This is the type that too many Americans neglect in their diet.

The other types of PUFAs, commonly found in highly processed foods don’t contribute the same benefits. Large amounts of omega-6 PUFAs, found in these highly refined oils and processed foods can actually have pro-inflammatory effects.²

So try to get more of your PUFAs coming from fish, avocados, nuts and seeds. Try not to eat too much of these fats coming from highly processed foods.

The bottom line is that we all need some fats in the diet for health in general. Moreover, we need specific types of dietary fats for good mental health in particular.

Dietary fats, chronic inflammation, and the food-mood link

Much of the link between mood and dietary fats is likely mostly explained by the role of chronic inflammation. Left unchecked, a chronic state of inflammation in the body will likely eventually impact the mood.

When eaten in large amounts, certain foods can contribute chronic inflammation. This is important to keep in mind considering a state of chronic inflammation can make symptoms of depression worse.

A study published in 2011 found a direct correlation between the amounts of trans fats and the risk of depression. Conversely, this study also found that those who ate higher amounts of olive oil (rich in MUFAs) had significantly lower levels of depression.³

Some researchers even believe chronic inflammation is a potential cause of depression, for some. This is referred to as the inflammatory theory of depression.⁴  Check out one of my past blog posts (linked here) to read more details about this link.

In conclusion – know your fats and choose wisely

Making healthful dietary changes can be hard. So don’t be too hard on yourself on your journey to healthful changes.

When it comes to knowing your fats, try and work fatty fish into your diet more regularly such as a couple times per week.

For snacks, include different nuts and seeds to provide essential fatty acids. Use extra virgin olive oil (EVOO) or avocado oil when preparing foods and choose EVOO-based dressings when you have salads.

For others who may decline to eat fish regularly and/or can’t stand different nuts and seeds, they might benefit from taking a high quality omega-3 supplement.

However, because the research shows mixed results on how helpful a supplement might be, I didn’t want to focus too much on this. Generally speaking, it’s better to focus on more of the whole foods. More of the natural sources of these essential fats, first.

References:

1. Le Port, A., Gueguen, A., Kesse-Guyot, E., Melchior, M., Lemogne, C., Nabi, H. Czernichow, S. (2012). Association between dietary patterns and depressive symptoms over time: a 10-year follow-up study of the GAZEL cohort. PloS one, 7(12), e51593. doi:10.1371/journal.pone.0051593
2. Innes JK, Calder PC. Omega-6 fatty acids and inflammation. Prostaglandins Leukot Essent Fatty Acids. 2018 May;132:41-48. doi: 10.1016/j.plefa.2018.03.004. Epub 2018 Mar 22. PMID: 29610056.
3. 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. doi:10.1371/journal.pone.0016268
4. Galecki P and Talarowska M. Inflammatory theory of depression. Psychiatria Polska. 2018, 52(3):437-447.