A population-based study on the nutritional status of children consuming macrobiotic diets was carried out in The Netherlands. Participants followed a macrobiotic diet based mainly on whole-grain cereals, pulses, and vegetables. Studies in children aged 0-10 y suggested that growth was retarded mainly between 6 and 18 mo. This was confirmed in a subsequent mixed-longitudinal study (including data on diet, anthropometry, blood chemistry, and pediatric examination) in 4-18 mo-old macrobiotic infants and a matched omnivorous control group. Ubiquitous deficiencies of energy, protein, vitamin B-12, vitamin D, calcium, and riboflavin were detected in macrobiotic infants, leading to retarded growth, fat and muscle wasting, and slower psychomotor development. Breast milk from macrobiotic mothers contained less vitamin B-12, calcium, and magnesium. Supplementation of the macrobiotic diet with fat (minimum 20-25 g/d), fatty fish (minimum 100-150 g/wk), and dairy products (minimum 150-250 g/d) is recommended.