Researchers studied 355 women in Morocco to understand why so many don’t get enough vitamin D, a nutrient crucial for strong bones and overall health. They found that the average woman consumed only about 2.89 micrograms of vitamin D daily—far below the recommended 5 micrograms. Fish, dairy products, and meat were the main sources, but most women still fell short. Interestingly, sun exposure was the strongest factor affecting vitamin D levels in the blood, more important than diet alone. The study suggests that women in rural areas and younger women aged 18-25 were at highest risk for vitamin D deficiency, highlighting the need for better nutrition education and sun safety practices.

The Quick Take

  • What they studied: How much vitamin D Moroccan women eat, where it comes from, and whether their blood levels of vitamin D are healthy
  • Who participated: 355 women aged 18 to 49 years old living in Meknes, Morocco, including both young adults and women approaching middle age from rural and urban areas
  • Key finding: Only 1 in 5 women got enough vitamin D from food (the recommended 5 micrograms daily), and sun exposure was the strongest factor affecting their vitamin D blood levels—more important than diet alone
  • What it means for you: If you’re a woman in Morocco or similar climates, you may need to spend more time in the sun safely and eat more vitamin D-rich foods like fish and dairy to maintain healthy vitamin D levels. However, this study was done in one specific region, so results may differ elsewhere.

The Research Details

Researchers recruited 355 women living in Meknes, Morocco and collected information about their eating habits and sun exposure using questionnaires that had been tested for accuracy. They also took blood samples to measure actual vitamin D levels using a laboratory test called chemiluminescence immunoassay, which is a precise method for detecting vitamin D. The researchers then used statistical methods to find patterns—specifically looking at which factors (like age, where someone lived, sun exposure, and diet) best predicted vitamin D levels in the blood.

This type of study, called a cross-sectional study, takes a snapshot of a population at one point in time rather than following people over months or years. It’s useful for identifying problems and patterns but can’t prove that one thing directly causes another. The researchers used advanced statistical techniques called LASSO regression to identify the most important predictors while avoiding false patterns that sometimes appear in data.

Understanding why vitamin D deficiency is so common in this population is important because vitamin D affects bone health, immune function, and overall well-being. By identifying the main sources of vitamin D and the strongest predictors of deficiency, researchers can develop targeted solutions—like recommending specific foods, sun exposure guidelines, or food fortification programs—rather than one-size-fits-all approaches.

This study used validated questionnaires (tools that have been tested and proven reliable) and a precise laboratory method to measure vitamin D. The sample size of 355 women is reasonably large for this type of research. However, the study only looked at women in one city in Morocco at one point in time, so results may not apply to all Moroccan women or women in other countries. The researchers adjusted their analysis for multiple factors, which strengthens the findings.

What the Results Show

The study revealed a significant vitamin D shortage in this population. The median daily intake was only 2.89 micrograms, with fewer than 20% of women meeting the 5 microgram daily recommendation. Fish was the most common dietary source (48% of vitamin D intake), followed by dairy products (24%) and meat (9%). When researchers looked at blood vitamin D levels, they found that women consuming more vitamin D from food had slightly higher levels—about 3 nanograms per milliliter higher for those in the higher intake groups compared to those eating the least.

However, the most striking finding was that sun exposure was far more important than diet in determining vitamin D levels. Women who spent at least 20 minutes daily in the sun had significantly higher vitamin D levels. The study found that sun exposure explained about 3% of the variation in vitamin D levels—more than any dietary factor alone.

Age and location made a big difference. Younger women aged 18-25 consumed significantly less vitamin D than older women. Rural women consumed about 2.73 micrograms daily compared to 3.18 micrograms for urban women, and rural women had much higher rates of deficiency (68% versus 32%). This gap likely reflects differences in food availability, dietary habits, and possibly sun exposure patterns between rural and urban areas.

The study also found that high body weight (adiposity) was associated with lower vitamin D levels in the blood, even after accounting for diet and sun exposure. This suggests that overweight individuals may need more vitamin D or have different vitamin D metabolism. Additionally, the researchers noted that despite adequate sun exposure in some women, vitamin D deficiency was still common, indicating that diet alone cannot compensate for inadequate sun exposure in this population.

This research aligns with previous studies showing that vitamin D deficiency is widespread in North Africa and the Middle East, even in sunny climates. The finding that sun exposure is more important than diet matches global research suggesting that dietary sources alone rarely provide sufficient vitamin D. However, this study uniquely highlights the specific dietary sources and the particular vulnerability of young and rural women in Morocco, which hadn’t been thoroughly documented before.

The study was conducted in only one city (Meknes), so results may not represent all Moroccan women or women in other regions. The questionnaires relied on women remembering what they ate, which can be inaccurate. The study was done at one point in time, so researchers couldn’t determine whether vitamin D levels change seasonally or over longer periods. The study couldn’t prove that low sun exposure causes low vitamin D—only that they’re connected. Additionally, the study didn’t measure actual sun exposure objectively (like with devices), relying instead on self-reported information.

The Bottom Line

Based on this research, women in Morocco should aim for at least 20 minutes of safe sun exposure daily (with appropriate sun protection to prevent skin damage). Increase consumption of vitamin D-rich foods, particularly fish and dairy products. If dietary intake remains low, food fortification programs (adding vitamin D to commonly eaten foods) could help. For women at highest risk—those aged 18-25, living in rural areas, or with high body weight—vitamin D supplementation may be worth discussing with a healthcare provider. These recommendations have moderate confidence because the study is well-designed but limited to one region.

These findings are most relevant to women living in Morocco and similar climates in North Africa. Young women aged 18-25 and rural women should pay particular attention. Women with limited sun exposure, those who are overweight, or those with dietary restrictions that limit fish and dairy should also consider these recommendations. However, the findings may not directly apply to women in other countries with different climates, food availability, and sun exposure patterns.

Improving vitamin D status takes time. If you increase sun exposure and dietary intake, you might see improvements in blood vitamin D levels within 4-8 weeks, though it can take 2-3 months for more significant changes. Benefits to bone health and immune function typically take longer—several months to a year of consistent adequate vitamin D status.

Want to Apply This Research?

  • Track daily sun exposure in minutes (aim for 20+ minutes) and log vitamin D-rich foods consumed (fish, dairy, fortified products). Monitor these weekly to identify patterns and progress toward goals.
  • Set a daily reminder to spend 20 minutes outdoors during midday hours. Add one fish or dairy serving to your daily meals. If using a nutrition app, search for and log vitamin D content of foods you eat to increase awareness of intake.
  • Monthly check-ins: review average daily sun exposure minutes and vitamin D food servings. Every 3 months, if possible, get blood vitamin D levels tested to see if changes are working. Adjust sun exposure and food intake based on results.

This research describes vitamin D status in a specific population in Morocco and should not be considered medical advice. Vitamin D needs vary by individual based on age, skin tone, geographic location, and health conditions. Before making significant changes to sun exposure or starting vitamin D supplements, consult with a healthcare provider, especially if you have kidney disease, heart disease, or take medications that interact with vitamin D. Pregnant and breastfeeding women should discuss vitamin D needs with their healthcare provider. This study was observational and cannot prove that low sun exposure or low dietary intake directly causes vitamin D deficiency in all individuals.