By David W. Brown
A growing body of research has documented that children on the autism spectrum are at higher risk for select micronutrient shortfalls—especially vitamin D and iron—owing to sensory-based food selectivity, limited dietary variety, and less outdoor time (which lowers skin production of vitamin D). The new Singapore cohort adds careful numbers to that picture: out of 222 autistic children who had vitamin D measured, 36.5% were insufficient/deficient; out of 236 who had iron studies, 37.7% had iron deficiency; and 15.6% of those with full blood counts had iron-deficiency anemia. Importantly, “picky eating” did not reliably predict who was deficient—meaning clinicians shouldn’t wait for pronounced feeding selectivity to screen.
These findings echo prior evidence. Earlier work has linked autism with lower vitamin D status and, in many cohorts, higher rates of iron deficiency compared with neurotypical controls. Recent reviews suggest that vitamin D status can correlate with symptom severity and that correcting deficiency may improve certain outcomes, though larger, longer trials are still needed.
Why vitamin D and iron matter
Vitamin D supports calcium–phosphate balance, bone health, immune regulation, and neurodevelopment. Food sources are limited; beyond sunlight, typical contributors are mushrooms (especially UV-exposed). Many public-health bodies note that routine vitamin D supplementation is often appropriate for children and other groups given widespread insufficiency, particularly when sunlight exposure is low.
Iron is essential for oxygen transport and for enzymes that shape attention, learning, memory, and motor development. Plant foods provide nonheme iron (lentils, beans, tofu/tempeh, pumpkin seeds, cashews, quinoa, dark leafy greens). Pairing plant iron with vitamin-C–rich foods (citrus, berries, peppers, tomatoes, broccoli) significantly boosts uptake.
Where a Whole-Food, Plant-Forward Pattern Fits—Including the P53 Diet
A thoughtfully planned whole-food, plant-forward diet—like the P53 Diet framework—emphasizes fruits, vegetables, legumes, whole grains, nuts, and seeds while removing ultra-processed items. Two big advantages of this pattern for families supporting autistic children:
- Higher nutrient density and fiber for the calories consumed. Diverse plant foods deliver broad micronutrient coverage (folate, magnesium, potassium, many phytonutrients) that typical “beige” kid diets lack. Large analyses show that shifting intake toward plant foods and away from red/processed meats is associated with better cardiometabolic profiles and lower risk of chronic disease over time—benefits that matter for the whole household.
- Built-in opportunities to optimize iron and vitamin D—if you’re intentional.
- You can reach iron needs with legumes (lentils, chickpeas, black beans), soy foods, seeds (pumpkin, sesame), nuts, dark greens, and fortified whole grains—and by routinely pairing them with vitamin-C-rich produce to magnify absorption.
- Vitamin D remains the exception: sunlight plus plant milks, often still won’t meet needs year-round; a supplement is commonly recommended for children by several expert groups. Your plan should treat vitamin D like a “must-check” nutrient. GET YOUR KIDS OUTSIDE MORE TO GET THEIR VITAMIN D!
Practical P53-style strategies for families
- Make the plate colorful and predictable. Sensory preferences are real. Offer a reliable structure (same plate/bowl, consistent mealtime cues) but vary the colors and textures within that structure—e.g., red lentil pasta with tomato-pepper sauce one night; chickpea pasta with lemon-broccoli another. Consistency lowers mealtime stress while nudging variety.
- Load iron + vitamin C together. Chili with black beans (iron) + diced tomatoes/bell peppers (vitamin C). Hummus (iron) + citrus segments. Tofu stir-fry with broccoli and pineapple.
- Lean on UV-exposed mushrooms. Sautéed or blended into sauces, they can add meaningful vitamin D—helpful, though still usually not enough alone.
- Mind the other “usual suspects.” Any plant-exclusive plan should also ensure vitamin B12 and iodine (iodized salt or nutritional yeast), with attention to calcium, zinc, and selenium as needed.
Bringing it together: why the P53 Diet is a strong fit
The P53 Diet’s core principles—whole, minimally processed plants; high diversity; avoidance of refined oils and ultra-processed foods; and a science-first approach—map cleanly onto what the evidence suggests for optimizing everyday health while guarding against common shortfalls:
- It raises overall diet quality, which supports healthy growth, GI function, and long-term cardiometabolic health for kids and adults alike.
- It makes iron coverage practical via legumes, soy, greens, seeds, and fortified grains—especially when recipes routinely pair these with vitamin-C-rich produce.
- It encourages a systems view: not just “fixing a number,” but improving sleep, movement, and whole-household food patterns that make nutrient sufficiency and metabolic health sustainable.
The new Nutrients study sharpens an increasingly consistent message: among children with autism who are tested, roughly four in ten can be low in vitamin D or iron, and you can’t reliably spot those kids by feeding behavior alone. As the authors note, “a significant proportion of almost 40% of children diagnosed with ASD … had vitamin D insufficiency/deficiency and/or iron deficiency.” That’s a call for routine screening and targeted nutrition support, not alarm.
A well-planned, whole-food, plant-forward pattern—like the P53 Diet—offers a powerful foundation for families: it elevates diet quality, improves long-term health markers, and, with a few smart habits (vitamin C with plant iron), closes the exact gaps highlighted by this research. Work with your pediatrician. With an evidence-aligned approach, plant-based eating becomes not just compatible with autism-informed nutrition—but one of the most practical ways to promote overall health for your child and your household. GET YOUR KIDS OUTDOORS MORE!
Reference:
Primary study: Koh MY, Lee AJW, Wong HC, Aishworiya R. Occurrence and Correlates of Vitamin D and Iron Deficiency in Children with Autism Spectrum Disorder. Nutrients. 2025;17(17):2738.