Vitamin D, A, and E: What A New Study Reveals About Chronic Disease Risk

Published on March 24, 2026

Higher incidence of multiple chronic diseases among those with lower vitamin D levels and higher vitamin A levels.

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A newly published study by Baron et al. examined how blood levels of vitamins D, A, and E relate to chronic diseases such as cardiovascular disease, diabetes, osteoporosis, and cancer. The findings unsurprisingly show high rates of vitamin D deficiency with a strong relationship to increased disease risk. The study also found important and potentially concerning associations with higher vitamin A levels, particularly in relation to chronic disease and cancer risk.

Importance of Vitamins D, A, and E for Health

Here is a brief refresher on what each of these fat-soluble vitamins does in the body:

Vitamin D

• Acts as a hormone and gene regulator
• Supports immune function, inflammation control, and calcium balance
• Essential for bone health, cardiovascular function, and metabolic health
• Deficiency is widespread globally and strongly linked to chronic disease

Vitamin A

• Important for vision, immune function, and cellular differentiation
• Plays a role in epithelial integrity and development
• Exists as retinol (animal sources) and carotenoids (plant sources)
• Both deficiency and excess can be problematic (U-shaped risk curve)

Vitamin E

• A powerful antioxidant that protects cell membranes
• Helps regulate oxidative stress and inflammation
• Supports cardiovascular and immune health
• Clinical benefits from supplementation remain inconsistent

Study Details

The Baron study analyzed data from 500 adults with a median age of approximately 61 years who were seen in general practice clinics across Italy. Researchers measured blood levels of 25-hydroxyvitamin D [25(OH)D], vitamin A (retinol), and vitamin E (alpha-tocopherol), while also collecting detailed demographic, clinical, and biochemical information. The goal was to evaluate how these vitamin levels relate to common chronic conditions, including hypertension, diabetes, coronary artery disease, osteoporosis, and cancer, within a real-world primary care population.

Key Finding #1: Vitamin D Insufficiency Is Widespread and Linked to Disease

The median vitamin D level was 20.4 ng/mL, and levels declined with age. Lower vitamin D levels were linked to:

• Osteoporosis
• Arterial hypertension
• Coronary artery disease (CAD)

“Our findings of significantly lower vitamin D concentrations in patients with osteoporosis, arterial hypertension, and coronary artery disease are consistent with extensive epidemiological evidence linking vitamin D deficiency to multiple chronic conditions.”

Key Finding #2: Higher Vitamin A Levels Are Linked to Chronic Disease

Even though average vitamin A levels were within the normal range, higher levels were consistently associated with increased disease incidence. Higher vitamin A levels were found in patients with:

• Hypertension
• Diabetes
• Cancer

The study also found that vitamin A was an independent predictor of:

• Having multiple chronic diseases
• Cancer presence

Risk increased progressively with higher vitamin A levels, such that individuals with levels above 800 µg/L had approximately 2.5x higher cancer prevalence (14.7% vs 5.8%).

“…recent evidence suggests that excessive vitamin A intake or elevated serum retinol concentrations may paradoxically increase cancer risk in certain populations. Our observation that vitamin A concentrations progressively increased with the number of chronic diseases suggests that elevated vitamin A may serve as a biomarker of underlying metabolic dysfunction or chronic inflammatory states rather than a causative factor.”

Key Finding #3: Vitamin A Tracks with Metabolic Dysfunction

Vitamin A levels were also positively correlated with BMI and levels of uric acid, creatinine, and inflammatory and hematologic markers. This suggests that vitamin A may be:

1. A marker of metabolic dysfunction, OR
2. Directly involved in disease processes, OR
3. Reflecting dietary patterns (especially animal-based intake)

The authors specifically highlight that an elevated vitamin A level is more likely from preformed retinol (animal foods and supplements), as plant-based carotenoids are tightly regulated and less likely to cause excess.

Vitamin A and Vitamin D: Is There a Relationship?

While this study did not demonstrate a strong direct statistical correlation between vitamin D and vitamin A levels, it highlights an important clinical contrast and potential interaction between these nutrients and raises several important biological considerations.

Both vitamins play central roles in

• Regulating gene expression
• Influencing immune function
• Modulating inflammatory pathways

Plus, they interact at the level of nuclear receptors (including VDR and RXR), suggesting overlapping and potentially interdependent effects in the body.  In a broader context, emerging research suggests that excess vitamin A may interfere with vitamin D signaling and metabolism, pointing to the importance of nutrient balance. This interplay represents an important area for future research and clinical application.

What About Vitamin E?

Vitamin E levels in this study were generally within the normal range and showed minimal associations with most chronic diseases. The only statistically significant finding was that individuals with osteoporosis had higher vitamin E levels compared to those without.

Vitamin E was also positively correlated with age, parathyroid hormone (PTH), and certain hematological markers such as hemoglobin and platelet counts, suggesting a possible relationship with oxidative stress and overall physiological demand rather than direct disease causation.

In Conclusion

Vitamin D deficiency remains a major public health issue. It is consistently and strongly associated with multiple chronic diseases yet remains underdiagnosed and undertreated.

While higher vitamin A levels were associated with increased risk of chronic disease and cancer in this study, it is important to interpret these findings with caution. Rather than indicating that vitamin A itself is driving disease, elevated serum levels may reflect altered metabolism and mobilization of vitamin A in response to underlying inflammation, metabolic dysfunction, or organ stress. Additionally, interactions between vitamins A and D may be clinically important.

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Measure Your Vitamin D and Other Important Nutrients

If you haven’t had your vitamin D levels checked recently, now is the time! With so many Americans still falling short, awareness is the first step toward change.

Measuring and calculating a supplementation amount to help reach and maintain a target level, or taking loading doses to correct deficiency faster, could possibly make all the difference in overall health, wellbeing, and how a current disease situation progresses. Test your level now!

Create your custom home blood spot kit by adding any of the following measurements, along with your vitamin D:

• Omega-3 Index (with or without Ratios AA:EPA and Omega-6:Omega-3)
• Magnesium (with additional Elements copper, zinc, selenium, mercury, and cadmium)
• hsCRP as a marker of inflammation and HbA1c as a marker of blood sugar health

Having and maintaining healthy vitamin D levels and other nutrient levels can help improve your health, now and for the future. Enroll and test your levels today, learn what steps to take to improve your status of vitamin D (see below) and other nutrients and blood markers, and take action! By enrolling in the GrassrootsHealth projects, you are not only contributing valuable information to everyone, you are also gaining knowledge about how you could improve your own health through measuring and tracking your nutrient status, and educating yourself on how to improve it.