Can Folate Prevent Obesity In Adolescents?

When Pigs Fly

Author: Dr. Stephen Chaney

The obesity epidemic has reached our children!

The prevalence of obesity in children and adolescents has increased 3-fold in the past 30 years.

According to the CDC:

In 2023 almost 20% of US children and adolescents (ages 6-17) were obese.

- And if you expand the category to overweight AND obese the percentage is over 30%.

The medical costs for treating obese children and adolescents in 2023 was $1.3 billion. That’s:

- $116 higher per person for obese children than children of normal weight.

- $310 higher per person for severely obese children than children of normal weight.

In the short-term, obesity in children and adolescents affects:

Growth
Hormone balance.
Self-image and psychological wellness.

Longer term, obesity in children and adolescents increases the risk of:

Heart Disease.
Diabetes and other metabolic disorders.
Certain cancers.
Premature death.

That’s why recent headlines suggesting that folate decreases the risk of obesity in children and adolescents were so intriguing.

We know that around 13% of boys and 40% of girls aged 12-15 have inadequate folate intake.

Could something as simple as a folate supplement decrease the risk of your child or teenager becoming obese?

Maybe. But before you rush out and buy folate supplements for your children, perhaps we should examine the study (F Yan et al. BMC Pediatrics, 26: 141, 2026) behind the headlines and see if there is a simpler explanation of the data.

How Was This Study Done?

This study utilized data from the US National Health and Nutrition Examination Survey (NHANES) that is conducted by the CDC on a continuous basis. This particular study utilized data collected from 49,693 Americans of all ages and ethnicities between 2009 and 2018.

For this study, children were classified as ages 6-11 years (4458 individuals) and adolescents as ages 12-19 years (4946 individuals).

Dietary folate intake was calculated from two 24-hour dietary recalls spaced 3-10 days apart.

The data only included folates from food sources and did not include any dietary supplements.

The first dietary recall interview was conducted in person and the second by phone.

Daily folate intake was calculated as folate intake in mcg per 1,000 calories of food (mcg/1,000 calories).

Finally, the participants were divided into quartiles: Q1 <143, Q2 143-182, Q3 182-235, Q4 ≥235, all in units of mcg/1,000 calories.

The study correlated folate intake with both overall overweight/obesity and central obesity.

Overweight/obesity was defined as a BMI ≥ than the sex- and age-specific 85^Th percentile for BMI.

Central obesity was defined as a waist circumference ≥ than the sex- and age-specific 90^th percentile corrected for height.

The data appeared to be convincing. For example:

In the total population of children plus adolescents (9,405 individuals):

Folate intake was negatively corelated with obesity.

When folate intake was analyzed as a continuous variable, for every unit increase of dietary folate intake:

- The percentage of overweight/obese children and adolescents decreased by 11%.

- The percentage of children and adolescents with central obesity decreased by 13%.

When folate intake was analyzed by quartiles.

- When quartile 2 (folate intake of 143-182) was compared to quartile 1 (folate intake <143), overweight/obesity decreased by 26% and central obesity by 23%.

- When quartile 3 (folate intake of 182-235) was compared to quartile 1, overweight/obesity decreased by 29% and central obesity by 26%.

- When quartile 4 (folate intake ≥235) was compared to quartile 1, overweight/obesity decreased by 35% and central obesity decreased by 36%.

As you might have guessed from the previous data, the effect of folate on the risk of obesity/overweight and central obesity was non-linear. There was an inflection point around 192 mcg/1,000 calories.

- When folate intake was below 192 mcg/1,000 calories, an increase of 100 mcg/1,000 calories decreased the risk of overweight/obesity and central obesity by 35%.

- When folate intake was above 192 mcg/1,000 calories, the effect of additional folate intake was not statistically significant.

When they broke down the data by age and gender:

The effect of folate intake on overweight/obesity and central obesity was not significant in children.

However, the effect of folate intake on overweight/obesity and central obesity was highly significant in adolescents and the effect was gender specific.

- When comparing folate intake in the Q4 range (≥235 mcg/1,000 calories) to the Q1 range (<143 mcg/1,000 calories) overweight/obesity:

- - Was reduced by 47% in men and 50% in women.

- When comparing folate intake in the Q4 range to the Q1 range central obesity:

- - Was reduced by 58% in women, but no statistically significant decrease was seen in men.

The authors concluded, “This cross-sectional study indicates that higher dietary folate is associated with lower odds of overweight/obesity and central obesity in children and adolescents in the United States. The association exhibits non-linear characteristics with potential thresholds of 190 mcg/1,000 calories and 195 mcg/1,000 calories, respectively. It is worth noting that this association is mainly significant in the adolescent population. This study reveals a possible dose-response relationship between dietary folate and obesity in children and adolescents.”

When Pigs Fly

It would be easy to accept the conclusions of these authors at face value. After all, the statistical correlation between higher folate intake and the risk of obesity in adolescents was very strong.

And the authors invoked a lot of impressive sounding metabolic mumbo-jumbo to explain how folate could affect appetite and body weight. [I’m qualified to call it mumbo-jumbo because I taught human metabolism to medical students for 40 years.]

You might be tempted to rush out and buy a folate supplement for your teenager, especially if they are starting to get a bit plump. But then, you might think, “Wait. It couldn’t be that simple. It just doesn’t sound plausible that folate intake has anything to do with obesity”.

The 16^th century English and Scotts had a phrase for impossible events. They were things that only happened “When pigs fly”. The original version of the saying was, “When pigs fly with their tails forward.” In other words, the pigs were not only flying. They were flying backwards.

What Could Go Wrong?

As I said above, the inverse association between folate intake and obesity in adolescents was very strong. What could go wrong? As Mark Twain said years ago, “There are lies. There are damn lies. And then there are statistics.” Let me explain.

This was an association study. Association studies measure the association between a single variable (folate intake) and an outcome (obesity). But, for the results to be reliable they need to be corrected for other variables that affect the same outcome. There are two kinds of variables – known variables and confounding variables.

The known variables for this study were age, sex, race, poverty level, physical activity, and total energy intake. They were all corrected for in this study.

“Confounding variables” are unknown variables that also affect the outcome of the study. But since they are unknown, they are not corrected for.

Let me give you a simplistic example of a confounding variable. Let’s say you were doing a study of dietary habits, and you found an association between ice cream consumption and mortality. You might conclude that ice cream consumption is bad for you. It increases your risk of dying.

But then you might remember that ice cream consumption increases during the summer. And then you might reason that people swim more during the summer, and there is a correlation between swimming and drowning deaths.

Swimming could be a confounding variable. To make sure that your initial conclusion that ice cream increases the risk of dying was correct, you would need to correct your data for swimming deaths during the summer and see if you still found a correlation between ice cream consumption and mortality.

In this study there was an inverse correlation between folate consumption and energy intake (calories consumed per day). The authors focused on the decreased energy intake associated with high folate intake. They postulated several mechanisms to explain this correlation, but their arguments were weak.

They should have been focusing on the other end of the spectrum. Adolescents in the lowest quartile of folate intake were consuming 10% more calories than those in the top quartile, yet their folate intake was 65% less.

The authors should have been asking, “How do you consume 10% more calories and end up with 65% less folate?” The answer is obvious.

The adolescents in the lowest quartile must be consuming a lot more highly processed foods – otherwise know as junk and convenience foods.

So, let’s ask what else we know about the situation:

Adolescents like to eat junk food.

There is strong correlation between consumption of highly processed foods and obesity.

The mechanisms underlying the correlation between highly processed foods and obesity have been well defined, and they have nothing to do with folate intake.

Highly processed food consumption was an obvious confounding variable, but the authors never asked what foods the adolescents in each folate quartile were eating.

This is sounding a lot like the correlation between ice cream consumption and death. The pigs are flying.

So, if you want your teens to be slim and healing, don’t reach for a folate supplement. Instead, try to convince your teens to cut back on their junk food consumption.

The Bottom Line

A recent study found a strong inverse association between folate intake and obesity in adolescents. For example:

When the highest folate intake was compared to the lowest, the risk of overweight and obesity was decreased by 35%.

However, you can’t believe every published study. In this case, the authors made a critical mistake in interpreting their data. The actual interpretation of their data should have been much different.

For more details about this study, what the study should have concluded, and 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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My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

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About The Author

Dr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years.

Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”.

Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

Since retiring from the University of North Carolina, he has been writing a weekly health blog called “Health Tips From the Professor”. He has also written two best-selling books, “Slaying the Food Myths” and “Slaying the Supplement Myths”. And most recently he has created an online lifestyle change course, “Create Your Personal Health Zone”. For more information visit https://chaneyhealth.com.

For the past 54 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.