Nutrition and Intelligence: What the Brain Needs to Perform
Omega-3, iron, iodine and B vitamins are critical for cognitive development. Here's how diet shapes IQ from pregnancy through adulthood.
The brain is the most energy-hungry organ in the body – about 2% of body weight but 20% of calories. What you eat directly affects how well it works.
Critical nutrients
Four nutrients have the strongest evidence: omega-3 fatty acids (especially DHA from oily fish) build neuronal membranes; iron transports oxygen and supports myelination; iodine is essential for thyroid function and brain development; B12 and folate for neural metabolism. Deficiency in childhood is linked to lower adult IQ.
The early years
The first 1,000 days – from conception to age two – are especially sensitive. Iodine deficiency in pregnancy can lower a child's later IQ by 7–13 points on average, according to WHO. See our article on nature vs nurture.
Adult cognition
In adults the effects are smaller but real. Mediterranean-style diets are linked to slower cognitive decline. Stable blood sugar through whole grains supports steadier performance on reasoning tasks. Try our free IQ test.
Test yourself
Curious where you'd land? Take our free online IQ test – no sign-up required.
FAQ
- Can diet raise IQ?
- In adults, diet has a modest effect on cognitive performance – mainly through blood sugar stability, hydration and long-term brain health. In children with nutrient deficiencies, correcting the deficiency can raise IQ substantially.
- Which nutrients matter most?
- Omega-3 fatty acids (especially DHA), iron, iodine and B vitamins (B12, folate) have the strongest evidence for brain development. Iodized salt is one of the most important public health measures of the 20th century.
- Does the Mediterranean diet help cognition?
- Yes. Adherence to a Mediterranean-style diet is associated with slower cognitive decline and lower dementia risk in older adults.