Do Omega-3s Reduce Depression?

Author: Dr. Stephen Chaney

We are in the midst of a mental health crisis. According to the latest statistics:

· 19% of adults in the United States have some form of mental illness.

· 16.5% of youth ages 6-17 have some form of mental illness.

· The 5 most commonly diagnosed forms of mental illness are anxiety, depression, post-traumatic stress disorder, bipolar disease, and ADHD.

Even worse, mental illness appears to be increasing at an alarming rate among young people. For example:

· Between 2005 and 2017 depression increased 52% among adolescents.

· Between 2002 and 2017 depression increased 63% in young adults.

· Between 1999 and 2014 suicides have increased 24% in young adults. In the past few years suicides have been increasing by 2% a year in this group.

Much has been written about the cause of this alarming increase in mental illness. The short answer is that we don’t really know. But the most pressing question is what do we do about it?

The medical profession relies on powerful drugs to treat the symptoms of mental illness. These drugs don’t cure the illness. They simply keep the symptoms under control. Plus, if you have ever listened closely to the advertisements for these drugs on TV, you realize that they all have serious side effects that adversely affect your quality of life.

My “favorite” example is drugs for anxiety and depression. You are told that one of the side effects is “suicidal thoughts”. That means that the very drug someone could be prescribed to prevent suicides might actually increase their risk of suicide. Why would anyone take such a drug?

If drugs are so dangerous, what about supplements? Do they provide a safe, natural alternative for reducing the symptoms of mental illness? Some supplement companies claim their products cure mental illness. Are their claims true or are they just trying to empty your wallet?

How is a consumer to know which of these supplement claims are true and which are bogus? Fortunately, an international team of scientists has scoured the literature to find out which supplements have been proven to reduce mental health symptoms.

How Was The Study Done?

This was a massive study (J. Firth et al, World Psychiatry, 18: 308-324, 2019. It was a meta-review of 33 meta-analyses of randomized, placebo-controlled trials with a total of 10,951 subjects. The clinical trials included in this analysis analyzed the effect of 12 nutrients, either alone or in combination with standard drug treatment, on symptoms associated with 10 common mental disorders.

To help you understand the power of this meta-review, let me start by defining the term “meta-analysis”. A meta-analysis combines the data from multiple clinical studies to increase the statistical power of the data. Meta-analyses are considered to be the gold standard of evidence-based evidence.

However, not all meta-analyses are equally strong. They suffer from the “Garbage-In, Garbage-Out” phenomenon. Simply put, they are only as strong as the weakest clinical studies included in their analysis.

That is the strength of this meta-review. It did not simply combine the data from all 33 meta-analyses. It used stringent criteria to evaluate the quality of each meta-analysis and weighted the data appropriately.

What Supplements Help Mental Health?

The strongest evidence was for omega-3 supplements. In the worlds of the authors:

· “Across 13 independent randomized control clinical trials in 1,233 people with major depression, omega-3 supplements reduced depressive symptoms significantly.”

o The average dose of omega-3s in these studies was 1,422 mg/day of EPA.

o The effect was strongest for omega-3 supplements containing more EPA than DHA and for studies lasting longer than 12 weeks.

o There was no evidence of publication bias in these studies. This is a very important consideration. Publication bias means that only studies with a positive effect were published while studies showing no effect were withheld from publication. That makes the effect look much more positive than it really is. The fact there was no evidence of publication bias strengthens this conclusion.

o Omega-3 supplements were more effective when used in combination with antidepressant drugs, but there was some evidence of publication bias in those studies.

· “Across 16 randomized control clinical trials reporting on ADHD symptom domains, significant benefits were observed for both hyperactivity/impulsivity and inattention.”

· Omega-3s had no significant effect on schizophrenia or bipolar disorder other than a mild reduction in depressive symptoms.

There was strong, but not definitive, evidence for folic acid and methylfolate supplements for depression.

· When used in conjunction with antidepressants both folic acid and methylfolate supplements “…were associated with significantly greater reductions in depressive symptoms compared to placebo, although there was large heterogeneity between trials.”

· The largest effects were observed with high dose methylfolate. In the words of the authors: “Two randomized control clinical trials examining a high dose (15 mg/day) of methylfolate administered in combination with antidepressants found moderate-to-large benefits for depressive symptoms.” However, to put this into perspective:

o 15 mg/day is 3,750% of the RDA. This is a pharmacological dose and should only be administered under the care of a physician.

o A smaller dose of 7.5 mg/day is ineffective.

o No comparison was made with folic acid at this dose, so we do not know whether folic acid would be equally effective.

· The authors concluded that there is emerging evidence for positive effects of vitamin D (>1,500 IU/day) for major depressive disorders and N-acetylcysteine (2-3 gm/day) in combination with drugs for mood disorders and schizophrenia. The term “emerging evidence” means there have been several recent studies reporting positive results, but more research is needed.

· The authors did not find evidence supporting the use of other vitamin and mineral supplements (E, C, zinc, magnesium, and inositol) for treating mental health disorders.

· The authors did not find enough high-quality studies to support claims about the effects of prebiotics or probiotics on mental health disorders.

Do Omega-3s Reduce Depression?

The evidence supporting the effectiveness of omega-3s in reducing symptoms of depression is strong. In the words of the authors: “The nutritional intervention with the strongest evidentiary support is omega-3, in particular EPA. Multiple meta-analyses have demonstrated that it has significant effects in people with depression, including high-quality meta-analyses with good confidence in findings…”

However, before you throw away your antidepressants and replace them with an omega-3 supplement, let me put this study into perspective for you.

· Depression can be a serious disease. If you just feel a little blue from time to time, try increasing your omega-3 intake. However, if you have major depression, don’t make changes to your treatment plan without consulting your physician.

· The best results were obtained when omega-3s were used in combination with antidepressants. This should be your starting point.

· Ideally, adding omega-3s to your treatment plan will allow your doctor to reduce or eliminate the drugs you are taking. That would have the benefit of reducing side effects associated with the drugs. However, I would like to re-emphasize this is a decision to take in consultation with your doctor. [My only caveat is if your doctor is unwilling to even consider natural approaches like omega-3 supplementation, it might be time to find a new doctor.]

· Finally, omega-3 supplementation is only one aspect of a holistic approach to good mental health. A healthy diet, exercise, supplementation, and stress reduction techniques all work together to keep your mind in tip-top shape.

The Bottom Line

There are lots of supplements on the market promising to cure depression and other serious mental health issues. Are they effective or are the claims bogus? Fortunately, a recent meta-review of 33 meta-analyses of high-quality clinical trials has answered that question. Here is their conclusion:

· The evidence is strongest for omega-3s and depression.

o The average dose of omega-3s in these studies was 1,422 mg/day of EPA.

o The effect was strongest for omega-3 supplements containing more EPA than DHA and for studies lasting longer than 12 weeks.

· There is fairly strong evidence for folate/folic acid supplements and depression, although there was large heterogeneity between trials.

· There is emerging evidence for vitamin D (>1,500 IU/day) and depression and N-acetylcysteine (2-3 gm/day) for depression and schizophrenia.

· Evidence for other supplements is currently inconclusive.

However, before you throw away your antidepressants and replace them with an omega-3 supplement, let me put this study into perspective for you.

· The best results were obtained when omega-3s were used in combination with antidepressants. That should be your starting point.

For more details, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

We Grow What We Eat

Author: Dr. Stephen Chaney

The subtitle of this week’s “Health Tips From the Professor” is “We Grow What We Eat”.

No, this is not about each of us starting a backyard garden and literally growing what we eat – although that would probably be a good idea for most of us. I’m actually talking about the bacteria that we “grow” in our intestine.

Most of you probably already know about the concept of “good” and “bad” intestinal bacteria.

Evidence suggests that the “bad” bacteria and yeast in our intestine can cause all sorts of adverse health effects:

There is mounting evidence that they can compromise our immune system.

There is also evidence that they can create a “leaky gut” (you can think of this as knocking holes in our intestinal wall that allow partially digested foods to enter the circulation where they can trigger inflammation and auto-immune responses).

There is some evidence that they can affect brain function and our moods.

They appear to convert the foods that we eat into cancer causing chemicals which can be absorbed into the bloodstream.

Studies in mice even suggest that they can make us fat.

The list goes on and on…

The “good bacteria” are thought to crowd out the “bad” bacteria and prevent many of the health problems they cause.

In case you’re thinking that it seems a bit far-fetched to think that our intestinal bacteria could affect our health, let me remind you that we have about 100 trillion bacteria in our intestine compared to about 10 trillion cells in our body. They outnumber us 10 to 1.

For years we have thought of “bad” bacteria and yeast as originating from undercooked, spoiled or poorly washed foods that we eat and the “good” bacteria as originating from foods like yogurt and probiotic supplements.

But most of us have not thought that the kinds of foods we choose to eat on a daily basis can affect the kinds of bacteria we “grow” in our intestine – until now. You’ve heard for years that “We are what we eat”. Well it now appears that we also “grow what we eat”. I’m referring to a recent study by G. D. Wu et al (Science, 334: 105-108, 2011).

Our Gut Bacteria Are What We Eat

I’m going to get a bit technical here (Don’t worry. There won’t be a quiz). Scientists refer to the population of bacteria in our intestines as our “microbiome”. Previous studies have shown that people from all over the world tend to have one of two distinct microbiomes (populations of bacteria) in their intestines – Bacteroides or Prevotella. [Again, don’t let the specialized scientific terminology scare you. These are just the names scientists have given to these two distinctive populations of intestinal bacteria].

What this study showed was that people who habitually consumed high-fat/low-fiber diets (diets containing predominantly animal protein and saturated fats) tended to have the Bacteroides bacteria in their intestine, while people who habitually consumed low-fat/high-fiber diets (diets that are primarily plant based and are high in carbohydrate and low in meat and dairy) tended to have the Prevotella bacteria in their intestine. And surprisingly this appears to be independent of sex, weight and nationality.

Is This Important?

The research defining these two distinct microbiomes (populations of intestinal bacteria) and showing that they are influenced by what we eat is very new. At this point in time we know relatively little about the health benefits and risks associated with the Bacteroides and Prevotella microbiomes.

For example:

Most of the studies on the health effects of “bad intestinal bacteria” were based on the identification of one or two “bad bacteria” in the gut – not on the hundreds of bacterial species found in the Bacteroides microbiome. So we can’t say for sure that the Bacteriodes microbiome found in people with diets high in animal protein and saturated fats will cause the same health problems as the “bad bacteria”. Nor do we know for sure how important a role the Bacteriodes microbiome plays in the health consequences of consuming that kind of diet.

Similarly, many of studies on the health benefits of “good intestinal bacteria” have been based on probiotic supplements containing one or two bacterial species – not the hundreds of bacterial species found in the Prevotella microbiome. So we can’t really say if probiotics or even the Prevotella microbiome will convey the same health benefits seen in populations who consume vegetarian diets.

However, now that do we know that we “grow what we eat” there are numerous studies ongoing to define the benefits and risks associated with each type of bacterial population.

For example, I shared a study with you recently which shows that the intestinal bacteria in people who eat a lot of animal protein convert carnitine (which is also found in meat) to a compound called TMAO, which may increase the risk of heart attacks, and that the conversion of carnitine to TMAO does not occur in people who consume a vegetarian diet ( see “Does Carnitine Increase Heart Disease Risk”)

Stay tuned! I’ll keep you updated as more information becomes available.

The Bottom Line:

Most of the studies I report on are ones that you can act on right away. This one is different. This study introduces a whole new concept – one that raises as many questions as it answers. This makes us ask those “what if” questions.

1) Previous studies have shown that most people have one of two different kinds of microbiomes (populations of bacteria) in their intestines. This study showed that diets high in animal protein and fat favored one kind of intestinal microbiome, while diets low in fat and high in fiber from fruits & vegetables favored another type of intestinal microbiome.

2) With a few exceptions we don’t know yet how important a role these intestinal microbiomes play in determining the health consequences of different diets. However, because our intestinal bacteria outnumber the cells in our body by 10:1, it is tempting to ask “What if?”

3) We also don’t yet know the extent to which probiotics (either from foods or supplements) can overcome the effects of a bad diet on our intestinal microbiome, but it is tempting to ask “What if?”

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.