Researchers in Brazil studied 363 teenagers to understand why many have unhealthy cholesterol levels. They looked at what the teens ate and compared three different eating patterns: Western (fast food-heavy), Healthy (lots of fruits and vegetables), and Traditional (local Brazilian foods). Surprisingly, they found that teenagers had high rates of cholesterol problems regardless of which eating pattern they followed. This suggests that diet alone may not explain why so many teens struggle with cholesterol—other factors like genetics, exercise, or stress might play a bigger role than previously thought.

The Quick Take

  • What they studied: Whether the types of foods teenagers eat are connected to having unhealthy cholesterol levels
  • Who participated: 363 teenagers (ages 17-18) from public schools in São Luís, Brazil. About 56% were girls, most came from families earning one to three minimum wages, and most had mothers who completed 8-12 years of school
  • Key finding: Nearly half of all teenagers (44.9%) had low ‘good cholesterol’ (HDL), but this problem showed up equally in teens eating Western, Healthy, or Traditional diets. The eating patterns studied did not explain the cholesterol problems
  • What it means for you: If you’re a teenager with high cholesterol, changing your diet alone might not be the complete answer. Talk to a doctor about other factors like family history, exercise, sleep, and stress that could also affect your cholesterol

The Research Details

This was a cross-sectional study, which means researchers took a snapshot in time of 363 teenagers and looked at their eating habits and cholesterol levels all at once. The teenagers filled out a detailed food frequency questionnaire where they reported what they typically eat. Researchers then used a statistical method called principal component analysis to group similar eating patterns together, creating three distinct diet types: Western (characterized by processed foods), Healthy (fruits, vegetables, whole grains), and Traditional (local Brazilian foods).

To measure cholesterol problems, the researchers checked multiple cholesterol markers including total cholesterol, LDL (bad cholesterol), HDL (good cholesterol), triglycerides, and two special cholesterol ratios. A teenager was considered to have a cholesterol problem if any of these markers were abnormal. The researchers used advanced statistical techniques to account for other factors that might influence cholesterol, like age and family background.

This research approach is important because it tries to understand real-world eating patterns rather than just looking at individual foods. By grouping foods into patterns, researchers can see how complete diets affect health. The advanced statistical methods they used help reduce bias and make the results more trustworthy. However, because this is a snapshot study rather than following teenagers over time, we can’t be completely certain about cause-and-effect relationships.

Strengths: The study included a reasonable sample size of 363 teenagers and used sophisticated statistical methods to control for confusing factors. The researchers carefully defined what counts as a cholesterol problem using multiple markers. Weaknesses: This is a cross-sectional study, so it shows associations but not definite causes. The study only looked at teenagers in one Brazilian city, so results may not apply everywhere. The food frequency questionnaire relies on teenagers remembering what they ate, which can be inaccurate. The study doesn’t explain why diet patterns didn’t predict cholesterol problems, leaving questions unanswered.

What the Results Show

The most striking finding was that dyslipidemia (unhealthy cholesterol levels) was very common among these teenagers—affecting most of the group studied. The most frequent problem was low HDL cholesterol (good cholesterol), found in 44.9% of teenagers. When researchers compared the three eating patterns, they found almost no difference in cholesterol problems between groups. Teenagers eating a Western diet, a Healthy diet, or a Traditional diet all had similar rates of cholesterol problems. The statistical analysis showed no meaningful connection between diet pattern and cholesterol health.

This unexpected result suggests that the eating patterns identified in this study—while different from each other—don’t adequately explain why teenagers have high cholesterol. The researchers used advanced statistical methods to account for other factors like age and family income, but even after doing this, diet patterns still didn’t predict cholesterol problems.

The study found that the majority of teenagers had at least one cholesterol abnormality, indicating that cholesterol problems are widespread in this population. The fact that low good cholesterol (HDL) was the most common problem is noteworthy because it’s often linked to lack of physical activity and poor lifestyle habits rather than just diet. The study also noted that most participants came from lower-income families, which could influence both diet choices and access to healthcare.

Previous research has often suggested that Western diets high in processed foods lead to worse cholesterol levels compared to healthier diets. This study’s finding that diet patterns didn’t significantly differ in their cholesterol effects challenges that assumption. However, this doesn’t mean diet is unimportant—it may mean that the way researchers grouped the foods into patterns didn’t capture the specific dietary components that actually matter for cholesterol. Other studies have found that individual nutrients (like saturated fat or fiber) matter more than overall eating patterns.

The biggest limitation is that this study only shows associations at one point in time—it can’t prove that diet causes cholesterol problems or that changing diet will improve cholesterol. The study only included teenagers from one city in Brazil, so results may not apply to teenagers in other countries or regions with different food availability. Teenagers self-reported what they eat, which is often inaccurate. The study didn’t measure physical activity, sleep, stress, or family history of cholesterol problems, which are all known to affect cholesterol levels. The three diet patterns identified may not have been different enough to show real health differences.

The Bottom Line

If you’re a teenager with high cholesterol: (1) Don’t assume diet is the only factor—talk to a doctor about family history, exercise, and other lifestyle factors (moderate confidence); (2) Still eat a healthy diet with fruits, vegetables, and whole grains, as this is good for overall health even if it didn’t show clear cholesterol benefits in this study (high confidence); (3) Get regular physical activity, which is known to improve good cholesterol levels (high confidence); (4) Get cholesterol checked regularly if you have family history of cholesterol problems (high confidence).

Teenagers with high cholesterol or family history of cholesterol problems should care about this research. Parents of teenagers should also pay attention. However, this study shouldn’t discourage healthy eating—it just suggests that diet alone may not be the complete answer. People living in lower-income areas where food choices are limited should know that cholesterol problems are common and worth monitoring. This research is less relevant to teenagers with normal cholesterol levels, though healthy eating is still important for overall health.

If you change your diet, it typically takes 4-12 weeks to see changes in cholesterol levels. However, this study suggests that diet changes alone may not fully solve cholesterol problems, so you should also focus on exercise (which can improve good cholesterol in 2-3 months) and other lifestyle factors. If you have a family history of cholesterol problems, you may need medication in addition to lifestyle changes—talk to a doctor about realistic expectations.

Want to Apply This Research?

  • Track daily physical activity minutes (aim for 60 minutes) and weekly servings of fruits and vegetables (aim for 5+ servings daily). Monitor cholesterol levels every 3-6 months if you have risk factors, and note any changes in energy levels or how you feel
  • Use the app to log meals and identify which specific foods you eat most often, rather than focusing on overall diet patterns. Set reminders for daily exercise, which appears to be important for cholesterol health. Track mood and stress levels, as these may influence cholesterol. Create a family health history section to note if relatives have cholesterol problems
  • Weekly: Log exercise and fruit/vegetable intake. Monthly: Review eating patterns and identify any processed foods you’re consuming frequently. Every 3 months: Check in with your doctor about cholesterol levels and discuss whether medication might be needed alongside lifestyle changes. Track trends over 6-12 months to see if your specific changes are helping

This research shows associations between diet and cholesterol in one group of Brazilian teenagers and cannot be applied as medical advice for all teenagers. Cholesterol levels are influenced by genetics, exercise, sleep, stress, and other factors beyond diet. If you are a teenager with high cholesterol or family history of cholesterol problems, consult with a healthcare provider for personalized evaluation and treatment recommendations. Do not make changes to diet or medication based solely on this study without medical guidance. This summary is for educational purposes and does not replace professional medical advice.