Down syndrome (trisomy 21) is the most common chromosomal abnormality, with a prevalence of approximately 1 in 700–1,000 live births. The phenotypic characteristics of Down syndrome specifically influence the nutritional needs and metabolic risks of these individuals, making targeted nutritional attention necessary that goes beyond general population recommendations. The main areas of nutritional concern in Down syndrome: tendency toward overweight and obesity, hypothyroidism (very common: 15–30% of individuals), malabsorption and celiac disease (increased frequency compared to the general population), chewing and swallowing difficulties, specific micronutrient deficiencies.

Weight Management: The Primary Challenge

The tendency toward overweight and obesity is one of the most common health issues in people with Down syndrome. Contributing factors are numerous: reduced basal metabolic rate (the body of many people with DS burns fewer calories at rest compared to people of the same age and body composition without DS), hypothyroidism (very frequent: further reduces basal metabolic rate), reduced physical activity (due to muscle hypotonia, social barriers, less independence in sports activities), difficulty applying healthy food choices independently (may require caregiver support), tendency toward hyperphagia (excessive eating) in some individuals. How to manage weight: moderate but targeted caloric reduction (not severe restrictions that could compromise growth in children or muscle mass in adults), regular adapted physical activity (see Special Olympics, water activities, walking), participatory nutrition education (people with DS can learn, with appropriate support, to make healthier food choices), collaboration with a dietitian for a caloric plan tailored to individual needs (which may be 30–50% lower than the norm for age and sex).

Hypothyroidism and Its Nutritional Impact

Hypothyroidism is present in 15–30% of people with Down syndrome (versus 2–3% of the general population) and is often subclinical in children (only blood tests show abnormalities, not classic symptoms). Hypothyroidism reduces basal metabolic rate, increases the tendency toward overweight, and affects cognitive function and energy levels. All people with Down syndrome should have thyroid hormone monitoring (TSH, FT4) at least annually. Levothyroxine therapy (synthetic T4) is the standard treatment. Nutritional interactions: levothyroxine must be taken on an empty stomach, at least 30–60 minutes before breakfast. Soy can interfere with absorption: avoid soy for 4 hours after taking the medication. Calcium and iron (supplements or food sources) reduce absorption: do not take simultaneously with levothyroxine. Nutrients that support thyroid function: iodine (fish, shellfish, iodized salt: essential for thyroid hormone production), selenium (nuts, legumes, fish: necessary for converting T4 to active T3), zinc (meats, legumes, nuts).

Celiac Disease and Intestinal Intolerances in Down Syndrome

Celiac disease (permanent gluten intolerance with autoimmune response) is present in 5–10% of people with Down syndrome, a prevalence 5–10 times higher than the average for the Italian population (1%). It is often asymptomatic or minimally symptomatic in people with DS (without classic gastrointestinal symptoms), making periodic screening necessary. Screening for celiac disease in Down syndrome: tissue transglutaminase antibodies (tTG IgA) and total IgA every 2–3 years even without symptoms. If positive: upper endoscopy with biopsy for confirmation. If celiac: strict and permanent gluten-free diet. Intestinal malabsorption: the muscle hypotonia that characterizes DS also affects intestinal muscles, producing slowed intestinal motility (frequent constipation) and in some cases malabsorption (even without celiac disease). Dietary strategies for constipation: increase fiber (fruits and vegetables at every meal), ensure adequate hydration, favor whole grains, consider using probiotics (Lactobacillus acidophilus, Bifidobacterium: can improve intestinal motility).

Specific Micronutrient Deficiencies in Down Syndrome

Some micronutrient deficiencies are particularly relevant in Down syndrome. Zinc: studies show blood zinc levels below average in many people with DS. Zinc is essential for immune function (people with DS have greater susceptibility to infections) and cognitive function. Food sources: meats, legumes, nuts, pumpkin seeds. Antioxidants (vitamin E, vitamin C, selenium, beta-carotene): the SOD1 gene (superoxide dismutase 1) is present in three copies in trisomy 21, producing an excess of antioxidant enzyme that paradoxically creates oxidative stress. Research is studying whether supplementation with additional antioxidants can compensate for this imbalance. Not yet conclusive for clinical recommendations. Vitamin D: frequently insufficient (as in the general Italian population and even more in those who reduce outdoor activity). Calcium: important for bone health (people with DS often have reduced bone density, even without clinically manifest osteoporosis). Omega-3 DHA: some studies show potential benefit on cognitive function in people with DS supplemented with DHA. Research is ongoing.

Meal Strategies in Down Syndrome: Autonomy and Participation

People with Down syndrome can, with appropriate support, develop good skills in food autonomy and active participation in food choices. How to support autonomy: involve the person in meal preparation (washing vegetables, mixing, setting plates): enjoyable motor activities that develop skills and self-esteem, use visual supports for food choices (illustrated list of healthy snacks that can be chosen independently, visual schedule of meals), teach recognition of hunger and satiety signals (many people with DS have difficulty with satiety regulation: educational support is fundamental), use augmentative and alternative communication (AAC) to facilitate expression of food preferences in people with verbal communication difficulties. Chewing difficulties: muscle hypotonia includes the chewing muscles. Foods that require intense and prolonged chewing can be difficult. It's not necessary to eliminate solid foods, but it can be helpful to: cut foods into smaller pieces, cook meats and hard vegetables a bit longer, favor cooking methods that soften (stews, soups), have a plan for oral sensory desensitization with a speech therapist if necessary.

Resources for Families in Italy

CoorDown (National Coordination of Down Syndrome Associations): the main Italian network. It has informational materials on health, nutrition, and inclusion. coordown.it. AIPD (Italian Association of People with Down Syndrome): present in many Italian cities with rehabilitation centers, social activities, and family support. aipd.it. Special Olympics Italy: adapted sports program for people with intellectual disabilities, including DS. Excellent for promoting physical activity and weight management. specialolimpicsitalia.it. Health guidelines for DS in Italy: the Italian Society of Pediatrics (SIP) has published recommendations for health surveillance of people with DS, including specific nutritional guidelines and screening schedules (thyroid, celiac disease, vision, hearing, heart). Available on the SIP website (sip.it). Regional reference centers for DS (present in all Italian regions) have multidisciplinary teams with specialized pediatricians, geneticists, child neuropsychiatrists, and dietitians: the reference point for integrated clinical management.

Nutrition and Cognitive Function in Down Syndrome

Research on nutrition and cognitive function in DS is an active and interesting area. Some nutrients show association with cognitive function. Omega-3 DHA: the brain is composed 60% of fats, with DHA as the main component of neuronal membranes. Studies on DHA supplementation in people with DS (including the DOXN21 trial from Johns Hopkins University) are evaluating whether DHA supplementation can improve cognitive functions. Preliminary results are positive but not yet definitive. Choline: an essential nutrient for acetylcholine production (a neurotransmitter involved in memory). Food sources: egg yolk, liver, legumes. Polyphenols and flavonoids: found in fruits, vegetables, green tea, dark chocolate. Some animal studies (mouse models with trisomy 21) show positive effects on neuronal plasticity. Clinical application in people not yet confirmed. Caution: many families of people with DS experiment with supplements and special diets with unproven cognitive claims (Nutrivene-D, Nutri-Chem: they lack evidence of efficacy in controlled studies). The risk is failing to recognize spontaneous developmental improvement as the effect of an expensive and unnecessary supplement.