Can Eating Fish Make Kids Smarter?

Written by Dr. Steve Chaney on . Posted in Can Eating Fish Make Kids Smarter

Will Omega-3s Turn Your Kid Into A Genius?

Author: Dr. Stephen Chaney

 

fish and fish oilYou have probably heard the old saying that fish is brain food. Is it true? Could eating fish make your kid(s) smarter?

It is certainly a plausible hypothesis. Many fish are good sources of long chain omega-3s (omega-3 fatty acids). Long chain omega-3s, particularly DHA, are an important part of the myelin sheath that coats our neurons.

We can think of the myelin sheath as analogous to the plastic coating on electrical wiring. The coating on electrical wires assures that the electrical signal gets from the beginning of the wire to the end without shorting out somewhere in the middle. The myelin sheath plays a similar role for our neurons.

A number of clinical studies suggest that adequate intake of fish and/or fish oil during pregnancy and the early stages of childhood is important for brain development. Other studies suggest that omega-3 supplementation may improve mental focus and reading skills in school-age children.

The current clinical study (J Liu et al, Scientific Reports, 7: 17961, 2017) looked at the effect of fish consumption in Chinese children aged 9-11 on their IQ score measured at age 12.

 

How Was The Study Done?

eating fish studyThis study included 541 Chinese school children who were part of an ongoing prospective longitudinal study. [That is scientific jargon meaning that one variable (diet) was measured at the beginning of the study and correlated with a second variable (IQ) measured several years later.]

The children were asked to fill out a food frequency questionnaire at ages 9-11. Fish intake frequency was measured by asking the children: “How often do you consume fish in a typical month?” The children were required to choose from:

  • seldom (less than 2 times per month),
  • sometimes (2-3 times per month), and
  • often (at least once a week).

It was assumed that the children might not have known what kind of fish their mothers prepared, so they were not asked to identify the kind of fish they ate.

At the time the children were enrolled in the program the investigators collected data on 13 other variables which might influence IQ. These variables included:

  • Gender
  • Parent’s education.
  • Parent’s occupation.
  • Parent’s marital status.
  • Whether the child was breastfed or not.
  • Duration of breastfeeding.
  • Home location.
  • Siblings.
  • Breakfast consumption (previous research has suggested breakfast intake may influence cognition).

At age 12 the IQ of the children was assessed using the Chinese version of a standard IQ test. The IQ tests were administered independently by two trained investigators to minimize investigator bias.

  • Verbal IQ was assessed based on:
    • Information Recall.
    • Comprehension
    • Arithmetic
    • Vocabulary
    • Recognition of Similarities.
  • Performance IQ was assessed based on:
    • Picture Arrangement.
    • Picture Completion.
    • Object Assembly.
    • Block Design.
    • Coding
    • Mazes
  • The Total IQ score was based on a combination of the Verbal and Performance scores.

The study measured the impact of fish consumption at ages 9-11 on IQ at age 12 and included statistical correction for other variables that might have influenced IQ.

 

Can Eating Fish Make Your Kids Smarter?

can eating fish make your kids smarter geniusWhen the children who frequently consumed fish (≥once a week) were compared to children who seldom consumed fish (˂2 times a month), their IQ scores were:

  • 75 points higher in verbal IQ.
  • 79 points higher in performance IQ.
  • 80 points higher in total IQ.

When the children who sometimes consumed fish (2-3 times a month) were compared to children who seldom consumed fish, their IQ scores were:

  • 92 points higher in verbal IQ.
  • 52 points higher in performance IQ.
  • 31 points higher in total IQ.

These data are consistent with previous studies showing that both dietary fish and omega-3 intake are associated with improved cognitive and academic performance in school age children.

[Note: This study also suggested that fish consumption may improve sleep quality, and the improved sleep quality may influence IQ. This is a complex subject. As such, it is best discussed in a future issue of “Health Tips From the Professor”.]

What Are the Strengths And Weaknesses Of This Study?

Strengths: The strengths of the study were:

  • It was a relatively large study.
  • Fish consumption was measured 1-3 years earlier than IQ.
  • thumbs upThe association between fish consumption and IQ remained significant after adjusting for 13 other variables known to influence IQ.
  • There was a clear dose-response relationship between the three levels of fish consumption.
  • It is consistent with a number of other studies showing that fish/omega-3 intake improves cognitive performance in children.

Thus, the authors concluded: “We believe the findings cannot be easily attributed to chance and that, instead, they reflect a reliable relationship between early, frequent fish consumption and later, improved cognitive performance.”

Weaknesses: The weaknesses of the study were:

  • thumbs down symbolIt did not ask what kinds of fish the children were eating. Some fish are much better sources of omega-3s than others, so it is not entirely accurate to attribute the higher IQ to omega-3 intake.
  • It did not assess the effect of “diet context” on the results. The Chinese diet is a primarily plant-based, low-fat diet. It is unclear whether eating fish once a week would have the same effect on IQ in the context of a typical American diet.
  • It is an “association study.” It simply measured the association between fish consumption and IQ. It does not prove cause and effect.

Finally, this is the first study to measure the correlation between fish consumption and IQ in this age group. Clearly, more experiments are needed to confirm these findings.

 

Will Omega-3s Turn Your Kid Into A Genius?

 

can eating fish make your kids smarter geniusWho wouldn’t want their children or grandchildren to have higher IQs?

However, I wouldn’t read too much into a study like this.

Let me share some perspective by way of a personal story. When I was in grade school, every child was given an IQ test and an aptitude test (I scored very low on anything mechanical in the aptitude test, which my wife can attest to.)

We children, as might be expected, shared our IQ scores. However, the scores didn’t prove to be as meaningful as we initially expected.

There were some kids in my class who had much higher IQ scores. In fact, they ranked in the genius category. However, many of them did mediocre in school and had undistinguished careers. In contrast, some of the kids who scored lower on their IQ tests had spectacular careers in their chosen fields.

The moral of this story is, of course, that there is a lot more than IQ that goes into success in school and success in life. With IQ, like many other things, it is important to have enough, but more is not necessarily better.

However, this study is consistent with many other studies suggesting that omega-3s, especially DHA, are important for brain development, mental focus, and cognitive skills in children. Consequently, if you have a child or grandchild, you want to make sure that they are getting enough omega-3s in their diet.

How much is enough, you might ask? Recommendations range from 70 mg/day EPA+DHA for children ages 1-3 to 100-150 mg/day EPA+DHA for older children, with about 2/3 of that coming from DHA.

While that may not sound like much, a recent study of 10, 942 American children ages 1-11 found that only around 25% of them were getting the recommended amount of EPA+DHA from their diet. In fact, most American children only get around 20-40 mg of EPA+DHA from their diet.

Fish are the preferred source of EPA+DHA because they also provide a healthy protein source, something else your child may not be getting enough of. The best fish sources of omega-3s are mackerel, salmon, sea bass, and sardines.

Of course, if your child is one of the many children who are not fond of omega-3-rich fish, you may want to consider an omega-3 supplement, especially one rich in DHA.

 

The Bottom Line

 A recent study analyzed the correlation between fish consumption and IQ in school aged children. The study found:

When the children who frequently consumed fish (≥once a week) were compared to children who seldom consumed fish (˂2 times a month), their IQ scores were:

  • 75 points higher in verbal IQ.
  • 79 points higher in performance IQ.
  • 80 points higher in total IQ.

When the children who sometimes consumed fish (2-3 times a month) were compared to children who seldom consumed fish, their IQ scores were:

  • 92 points higher in verbal IQ.
  • 52 points higher in performance IQ.
  • 31 points higher in total IQ.

These data are consistent with previous studies showing that both dietary fish and omega-3 intake are associated with improved cognitive and academic performance in school age children.

For more details on the study and perspective on what the study means for you, 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.

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Latest Article

Can Plant-based Diets Be Unhealthy?

Posted September 10, 2019 by Dr. Steve Chaney

Do Plant-Based Diets Reduce Heart Disease Deaths?

Author: Dr. Stephen Chaney

 

plant-based diets vegetablesPlant-based diets have become the “Golden Boys” of the diet world. They are the diets most often recommended by knowledgeable health and nutrition professionals. I’m not talking about all the “Dr. Strangeloves” who pitch weird diets in books and the internet. I am talking legitimate experts who have spent their life studying the impact of nutrition on our health.

Certainly, there is an overwhelming body of evidence supporting the claim that plant-based diets are healthy. Going on a plant-based diet can help you lower blood pressure, inflammation, cholesterol and triglycerides. People who consume a plant-based diet for a lifetime weigh less and have decreased risk of heart disease, diabetes, and cancer.

But, can a plant-based diet be unhealthy? Some people consider a plant-based diet to simply be the absence of meat and other animal foods. Is just replacing animal foods with plant-based foods enough to make a diet healthy?

Maybe not. After all, sugar and white flour are plant-based food ingredients. Fake meats of all kinds abound in our grocery stores. Some are very wholesome, but others are little more than vegetarian junk food. If you replace animal foods with plant-based sweets, desserts, and junk food, is your diet really healthier?

While the answer to that question seems obvious, very few studies have asked that question. Most studies on the benefits of plant-based diets have compared population groups that eat a strictly plant-based diet (Seventh-Day Adventists, vegans, or vegetarians) with the general public. They have not looked at variations in plant food consumption within the general public. Nor have they compared people who consume healthy and unhealthy plant foods.

This study (H Kim et al, Journal of the American Heart Association, 8:e012865, 2019) was designed to fill that void.

 

How Was The Study Done?

plant-based diets studyThis study used data collected from 12,168 middle aged adults in the ARIC (Atherosclerosis Risk in Communities) study between 1987 and 2016.

The participant’s usual intake of foods and beverages was assessed by trained interviewers using a food frequency questionnaire at the time of entry into the study and again 6 years later.

Participants were asked to indicate the frequency with which they consumed 66 foods and beverages of a defined serving size in the previous year. Visual guides were provided to help participants estimate portion sizes.

The participant’s adherence to a plant-based diet was assessed using four different well-established plant-based diet scores. For the sake of simplicity, I will include 3 of them in this review.

  • The PDI (Plant-Based Diet Index) categorizes foods as either plant foods or animal foods. A high PDI score means that the participant’s diet contains more plant foods than animal foods. A low PDI score means the participant’s diet contains more animal foods than plant foods.
  • The hPDI (healthy plant-based diet index) is based on the PDI but emphasizes “healthy” plant foods. A high hPDI score means that the participant’s diet is high in healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, coffee and tea) and low in animal foods.
  • The uPDI (unhealthy plant-based diet index) is based on the PDI but emphasizes “unhealthy” plant foods. A high uPDI score means that the participant’s diet is high in unhealthy plant foods (refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts) and low in animal foods.

For statistical analysis the scores from the various plant-based diet indices were divided into 5 equal groups. In each case, the group with the highest score consumed the most plant foods and least animal foods. The group with the lowest score consumed the least plant foods and the most animal foods.

The health outcomes measured in this study were heart disease events, heart disease deaths, and all-cause deaths. Again, for the sake of simplicity, I will only include 2 of these outcomes (heart disease deaths and all-cause deaths) in this review. The data on deaths were obtained from state death records and the National Death Index. (Yes, your personal information is available on the web even after you die.)

 

Do Plant-Based Diets Reduce Heart Disease Deaths?

plant-based diets reduce heart deathsThe participants in this study were followed for an average of 25 years.

The investigators looked at heart disease deaths over the 25 years and compared people with the highest intake of plant foods to people with the highest intake of red meat and other animal foods. The results were:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, coffee and tea) had a 19-32% lower risk of dying from heart disease than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods (refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts) had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

When the investigators looked at all-cause deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had an 11-25% lower risk of dying from any cause than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

What Else Did The Study Show?

The investigators made a couple of other interesting observations:

  • The association of the overall diet with heart disease and all-cause deaths was stronger than the association of individual food components. This underscores the importance of looking at the effect of the whole diet on health outcomes rather than the “magic” foods you hear about on Dr. Strangelove’s Health Blog.
  • Diets with the highest amount of healthy plant foods were associated with higher intake of carbohydrates, plant protein, fiber, and micronutrients, including potassium, magnesium, iron, vitamin A, vitamin C, folate, and lower intake of saturated fat and cholesterol.
  • Diets with the highest amount of unhealthy plant foods were associated with higher intake of calories and carbohydrates and lower intake of fiber and micronutrients.

The last two observations may help explain some of the health benefits of plant-based diets.

 

Can Plant-Based Diets Be Unhealthy?

plant-based diets unhealthy cookiesNow, let’s return to the question I asked at the beginning of this article: “Can plant-based diets be unhealthy?” Although some previous studies have suggested that unhealthy plant-based diets might increase the risk of heart disease, this study did not show that.

What this study did show was that an unhealthy plant-based diet was no better for you than a diet containing lots of red meat and other animal foods.

If this were the only conclusion from this study, it might be considered a neutral result. However, this result clearly contrasts with the data from this study and many others showing that both plant-based diets in general and healthy plant-based diets reduce the risk of heart disease deaths and all-cause deaths compared to animal-based diets.

The main message from this study is clear.

  • Replacing red meat and other animal foods with plant foods can be a healthier choice, but only if they are whole, minimally processed plant foods like whole grains, fruits, vegetables, nuts, legumes, coffee and tea.
  • If the plant foods are refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts, all bets are off. You may be just as unhealthy as if you kept eating a diet high in red meat and other animal foods.

There is one other subtle message from this study. This study did not compare vegans with the general public. Everyone in the study was the general public. Nobody in the study was consuming a 100% plant-based diet.

For example:

  • The group with the highest intake of plant foods consumed 9 servings per day of plant foods and 3.6 servings per day of animal foods.
  • The group with the lowest intake of plant foods consumed 5.4 servings per day of plant foods and 5.6 servings per day of animal foods.

In other words, you don’t need to be a vegan purist to experience health benefits from adding more whole, minimally processed plant foods to your diet.

 

The Bottom Line

A recent study analyzed the effect of consuming plant foods on heart disease deaths and all-cause deaths over a 25-year period.

When the investigators looked at heart disease deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had a 19-32% lower risk of dying from heart disease than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

When the investigators looked at all-cause deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had an 11-25% lower risk of dying from any cause than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

The main message from this study is clear.

  • Replacing red meat and other animal foods with plant foods can be a healthier choice, but only if they are whole, minimally processed plant foods like whole grains, fruits, vegetables, nuts, legumes, coffee and tea.
  • If the plant foods are refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts, all bets are off. You may be just as unhealthy as if you kept eating a diet high in red meat and other animal foods.

A more subtle message from the study is that you don’t need to be a vegan purist to experience health benefits from adding more whole, minimally processed plant foods to your diet. The people in this study were not following some special diet. The only difference was that some of the people in this study ate more plant foods and others more animal foods.

For more details on the study, 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.

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