Researchers studied 2,078 college students in Italy to see if they could measure how healthy someone’s diet is just by looking at their skin. They found that people who eat more fruits and vegetables have a special yellow-orange color in their skin caused by natural plant pigments called carotenoids. Students who ate more than 2 servings of vegetables and 3 servings of fruit daily had noticeably higher skin color scores than those who ate less. The study also found that smoking and higher body weight were linked to lower skin carotenoid levels. This simple skin test could help doctors identify who might need to eat healthier.

The Quick Take

  • What they studied: Can we tell how healthy someone’s diet is by measuring the color of their skin, and how does this relate to their weight, exercise habits, and lifestyle choices?
  • Who participated: 2,078 university students in Italy, average age around 20s, with normal body weights on average. Researchers measured their height and weight, asked about their eating habits and lifestyle, and used a special device to measure carotenoid levels in their skin.
  • Key finding: Students who ate more than 2 servings of vegetables and more than 3 servings of fruit per day had significantly higher skin carotenoid levels (391.67 vs 349.27 on the measurement scale, p < 0.0001). This means eating more produce creates a measurable change in your skin color that reflects your diet quality.
  • What it means for you: Your skin color might be a simple way to check if you’re eating enough fruits and vegetables. If you’re not seeing the healthy glow, it could be a sign to eat more produce. However, this is just one study in young, healthy adults, so talk to your doctor before making major diet changes based on this alone.

The Research Details

This was a cross-sectional study, which means researchers looked at a large group of people at one point in time rather than following them over months or years. All 2,078 students at the University of Calabria in Italy were measured for their height and weight, asked detailed questions about what they eat and their lifestyle habits using two different questionnaires (one about Mediterranean diet patterns and one about Mediterranean lifestyle), and had their skin carotenoid levels measured using a device called the Veggie Meter.

The researchers used statistical tests to compare different groups of students. For example, they compared students who ate lots of fruits and vegetables to those who didn’t, and looked at how smoking and body weight affected the skin carotenoid measurements. They also used a more advanced statistical method called multiple regression analysis to see which factors were most important in predicting skin carotenoid levels while accounting for other variables at the same time.

This approach is practical because it doesn’t require following people for years, and it gives researchers a quick snapshot of the relationship between diet, lifestyle, and this measurable skin marker in a real-world population.

Cross-sectional studies like this are valuable for identifying patterns and connections between different health factors. By measuring skin carotenoids directly rather than just asking people what they eat, the researchers used an objective biological marker that can’t be faked or misremembered. This is important because people often forget or underestimate how much they actually eat. The study’s large sample size of over 2,000 students makes the findings more reliable than a smaller study would be.

Strengths of this study include its large sample size, the use of an objective measurement tool (the Veggie Meter) rather than relying only on what people report, and the use of established questionnaires to measure diet and lifestyle. The study was conducted in a real-world setting with university students. However, the study only looked at young, healthy college students in Italy, so the results might not apply to older people, people with health conditions, or people from different countries with different food cultures. The study is also cross-sectional, meaning we can see associations but can’t prove that eating more vegetables causes higher skin carotenoids (though this is very likely true).

What the Results Show

The main finding was clear and striking: students who ate more fruits and vegetables had noticeably higher skin carotenoid levels. Specifically, those eating more than 2 servings of vegetables and more than 3 servings of fruit daily had skin carotenoid scores of 391.67, compared to 349.27 for those eating less. This difference was highly statistically significant (p < 0.0001), meaning there’s less than a 1 in 10,000 chance this happened by random luck.

When researchers looked at where the fruits and vegetables came from, they found something interesting: students who got their produce from home gardens had slightly higher carotenoid levels (368.28) than those buying from markets (357.84). While this difference was smaller and less dramatic, it was still statistically significant.

The study also revealed several other important associations. Male students had higher skin carotenoid levels than female students. Older students in the group had higher levels than younger ones. Students who followed the Mediterranean diet pattern more closely had higher carotenoid levels. Importantly, smoking was linked to lower carotenoid levels, and higher body weight (BMI) was also associated with lower levels.

Overall, the students in this study had medium adherence to the Mediterranean diet pattern and normal body weights on average, with a mean BMI of 23.30, which is considered healthy.

Beyond the main findings about fruit and vegetable intake, the study revealed that smoking habits significantly affected skin carotenoid levels. Smokers had noticeably lower levels than non-smokers, suggesting that smoking may interfere with how the body uses or stores these beneficial plant pigments. Body weight also mattered—students with higher BMI scores had lower carotenoid levels, even though most students were at healthy weights. This suggests that maintaining a healthy weight is connected to better fruit and vegetable intake or better absorption of these nutrients. The study also found that overall adherence to a Mediterranean lifestyle pattern (which includes diet, physical activity, and other healthy habits) was positively associated with skin carotenoid levels, indicating that this is part of a broader healthy lifestyle picture rather than just about eating vegetables.

This study builds on existing research showing that carotenoids from fruits and vegetables are important for health and that skin carotenoid levels can reflect dietary intake. Previous studies have shown that carotenoids act as antioxidants in the body and may help prevent chronic diseases like heart disease, diabetes, and certain cancers. This study adds to that knowledge by showing that skin carotenoid measurement is a practical, objective way to assess fruit and vegetable intake in young adults. It also confirms what nutritionists have long recommended: eating more produce is linked to better overall health markers. The finding that garden-grown produce had slightly higher carotenoid levels aligns with some research suggesting that homegrown vegetables may have different nutrient profiles than commercially grown ones.

This study has several important limitations to keep in mind. First, it only included college students in Italy, who tend to be young and relatively healthy. The results might be different for older people, people with chronic diseases, or people from different countries with different food cultures and availability of produce. Second, the study is cross-sectional, meaning it’s a snapshot in time. We can see that higher fruit and vegetable intake is associated with higher skin carotenoids, but we can’t prove that eating more vegetables causes the higher levels (though this is very likely). Third, the study relied on questionnaires for dietary information, which can be inaccurate if people don’t remember or don’t want to report their eating habits honestly. Finally, the study didn’t measure other important health factors like physical fitness, sleep quality, or stress levels, which could also affect skin carotenoid levels.

The Bottom Line

Based on this research, eating more than 2 servings of vegetables and more than 3 servings of fruit daily appears to be associated with better health markers as measured by skin carotenoid levels. This aligns with standard nutritional guidelines recommending increased fruit and vegetable intake. The evidence is moderate strength because this is one cross-sectional study in a specific population. Additionally, avoiding smoking and maintaining a healthy body weight appear to support better carotenoid levels. These recommendations are most confident for young, healthy adults but likely apply more broadly.

Young adults and college-age people should pay attention to these findings, as this is the population studied. However, the general principle that eating more fruits and vegetables is healthy applies to everyone. People trying to improve their diet quality, those concerned about chronic disease prevention, and anyone interested in objective ways to track their nutrition should find this relevant. The findings are less directly applicable to very young children, elderly people, or people with certain medical conditions that affect nutrient absorption, though the basic principle of eating more produce still holds.

If you increase your fruit and vegetable intake, you probably won’t see changes in skin carotenoid levels overnight. Carotenoids accumulate in the skin over weeks to months as you consistently eat more produce. Most research suggests that meaningful changes in skin color from increased carotenoid intake take at least 2-4 weeks of consistent higher intake, with more dramatic changes visible after 8-12 weeks. However, the health benefits of eating more fruits and vegetables may start happening sooner at the cellular level, even if you can’t see the skin color change yet.

Want to Apply This Research?

  • Track daily servings of fruits and vegetables consumed. Set a goal of at least 2 servings of vegetables and 3 servings of fruit daily, and log each serving in the app. Include notes about whether produce came from a garden or store, as this may affect nutrient content.
  • Use the app to set daily reminders to eat fruits and vegetables at each meal. Create a shopping list feature that prioritizes produce, and set weekly goals to try one new fruit or vegetable. Consider adding a photo feature where users can take pictures of their meals to visually track produce intake over time.
  • Have users take periodic photos of their skin (same location, same lighting) every 4 weeks to visually track any changes in skin tone that might reflect increased carotenoid levels. Pair this with consistent logging of fruit and vegetable intake. Create a dashboard showing the correlation between daily produce servings and skin appearance over time. Include reminders to maintain consistent intake, as the benefits depend on regular consumption rather than occasional high intake.

This research shows associations between skin carotenoid levels and fruit/vegetable intake in young, healthy college students, but cannot prove cause-and-effect relationships. The findings may not apply to all age groups, populations, or people with medical conditions. Skin carotenoid measurement should not replace standard medical assessments or blood tests for evaluating nutritional status or disease risk. Before making significant dietary changes or using skin carotenoid measurement as a health assessment tool, consult with your healthcare provider or a registered dietitian, especially if you have existing health conditions, take medications, or have specific nutritional concerns. This information is for educational purposes and should not be considered medical advice.