Researchers studied 1,579 American teenagers to see if eating foods with special plant compounds called lignans affects where their body stores fat. They measured these compounds in urine and used special scans to map where fat was stored on each teen’s body. They found that teens who consumed more lignans tended to store fat in healthier patterns—specifically less in the belly area and more in the hip and thigh area. This is important because where your body stores fat matters for your health, not just how much fat you have. The study suggests that eating more lignan-rich foods might be a simple way to help teenagers develop healthier body composition as they grow.

The Quick Take

  • What they studied: Whether eating foods containing lignans (natural plant compounds) affects where teenagers store body fat and whether some fat storage patterns are healthier than others.
  • Who participated: 1,579 American teenagers aged 12-19 from a national health survey conducted between 2003 and 2006. The group represented different races, ethnicities, and socioeconomic backgrounds across the United States.
  • Key finding: Teenagers who consumed more lignans showed a 0.7% decrease in belly fat relative to hip fat for every unit increase in lignan intake. Additionally, one type of lignan compound was linked to more fat storage in the hip and thigh area, which is considered a healthier fat storage pattern.
  • What it means for you: Eating more lignan-rich foods (like seeds, whole grains, and legumes) may help your body store fat in less risky places. However, this is one study showing an association, not proof that lignans directly cause this change. More research is needed before making major dietary changes based solely on this finding.

The Research Details

This was a cross-sectional study, meaning researchers collected information from teenagers at one point in time rather than following them over months or years. The researchers used data from the National Health and Nutrition Examination Survey (NHANES), a large government study that tracks American health. They measured lignan intake indirectly by testing urine samples for two compounds (enterolactone and enterodiol) that the body produces when you eat lignans. They used a special scanning technology called dual-energy X-ray absorptiometry (DEXA) to precisely measure where fat was located on each teenager’s body. The researchers then used statistical models to look for connections between lignan levels and fat distribution patterns, adjusting for other factors like age, sex, race, and overall body weight that might affect the results.

Using urine biomarkers to measure lignan intake is more accurate than relying on teenagers to remember what they ate. The DEXA scanning technology provides precise measurements of fat location rather than just overall weight. By adjusting for other factors, the researchers could better isolate the specific effect of lignans. This approach helps separate the lignan effect from other things that influence where fat gets stored.

This study has several strengths: it used a large, nationally representative sample of American teenagers, employed objective measurement methods for both lignan intake and fat distribution, and adjusted for multiple factors that could influence results. However, because it’s a cross-sectional study (snapshot in time), it cannot prove that lignans cause healthier fat distribution—only that they’re associated with it. The study cannot rule out that teenagers who eat more lignans also have other healthy habits that affect fat storage. Additionally, the data is from 2003-2006, so dietary patterns may have changed since then.

What the Results Show

The main finding was that higher urinary enterolactone levels (indicating more lignan consumption) were significantly linked to a lower ratio of belly fat to hip fat. Specifically, for every unit increase in enterolactone, the belly-to-hip fat ratio decreased by 0.007 units. This relationship was statistically significant (P = 0.008), meaning there’s less than a 1% chance this finding occurred by random chance. The researchers confirmed this relationship was linear, meaning it didn’t have any surprising jumps or curves—more lignans simply meant progressively better fat distribution patterns. A second lignan compound called enterodiol showed a positive association with hip and thigh fat storage (β = 0.360, P = 0.028), suggesting it may encourage fat storage in these areas, which is generally considered healthier than belly fat storage. These findings suggest that different lignan compounds may work in slightly different ways in the body.

The study examined how these relationships held up after adjusting for various factors like age, sex, race, ethnicity, body mass index, physical activity level, and calorie intake. The associations remained statistically significant even after these adjustments, suggesting the lignan effect wasn’t simply due to teenagers who eat more lignans being healthier in other ways. The researchers also tested whether the relationships were linear (straight line) or curved, finding that the relationship between enterolactone and fat distribution was indeed linear, making it easier to predict outcomes.

Most previous research on lignans and body composition focused on adults, making this one of the first studies to examine this relationship in teenagers. The findings align with some adult studies suggesting lignans may influence fat storage patterns, but the teenage body may respond differently due to ongoing growth and hormonal changes. This study expands our understanding by showing that lignans may be important for metabolic health even during the teenage years when body composition is still developing.

The study cannot prove cause-and-effect because it’s a snapshot in time rather than following teenagers over years. Teenagers who eat more lignans likely have other healthy habits that could also affect fat storage. The data is from 2003-2006, so current teenagers’ diets and lifestyles may differ. The study measured lignan intake indirectly through urine markers rather than directly tracking food intake, which could introduce measurement errors. Additionally, the study was observational, so unmeasured factors (like genetics, stress, or sleep patterns) could influence the results.

The Bottom Line

Based on this research, eating more lignan-rich foods (seeds, whole grains, legumes, and some vegetables) appears to be associated with healthier fat distribution patterns in teenagers. However, this is one study showing an association, not definitive proof. The evidence is moderate—promising but not conclusive. Teenagers should focus on overall healthy eating patterns that include whole grains, legumes, seeds, and vegetables for multiple health benefits, not just for lignans. This should be part of a broader approach including regular physical activity and adequate sleep.

This research is most relevant to teenagers concerned about their body composition and where their body stores fat. Parents and healthcare providers working with teenagers on metabolic health may find this information useful. Teenagers with family histories of metabolic diseases or those struggling with weight management might benefit from increasing lignan-rich foods. However, this study doesn’t apply to very young children or adults, whose bodies work differently. Anyone with specific health concerns should consult their doctor before making major dietary changes.

Changes in body fat distribution typically take weeks to months to become noticeable, not days. If a teenager increases lignan intake through dietary changes, they might expect to see measurable changes in body composition over 8-12 weeks, though individual results vary. The benefits would likely be gradual and most noticeable when combined with regular physical activity.

Want to Apply This Research?

  • Track daily servings of lignan-rich foods (seeds, whole grains, legumes, and certain vegetables) and aim for 2-3 servings daily. Log specific foods like flaxseeds, sesame seeds, whole wheat bread, lentils, and beans to monitor intake patterns.
  • Replace refined grain products with whole grain versions and add one lignan-rich food to each meal. For example: sprinkle seeds on breakfast, include legumes in lunch, and add vegetables to dinner. Start with small additions to make the change sustainable.
  • Track lignan-rich food intake weekly and monitor body composition changes monthly through measurements or progress photos rather than scale weight alone. Note energy levels and how clothes fit as additional indicators of body composition changes. Combine dietary tracking with activity logs to see the full picture of lifestyle factors affecting body composition.

This research shows an association between dietary lignans and fat distribution patterns in teenagers, but does not prove that lignans directly cause these changes. This study is observational and cannot establish cause-and-effect relationships. Individual results vary based on genetics, overall diet, physical activity, and other lifestyle factors. Teenagers should not make significant dietary changes based solely on this research. Consult with a healthcare provider, registered dietitian, or nutritionist before making major dietary modifications, especially if you have existing health conditions or take medications. This information is for educational purposes and should not replace professional medical advice.