Nutrition

Nutrition is important for good health. In conditions like SMA, malnutrition and a poor diet can contribute to weakness of the breathing muscles and a weaker immune system.

A balanced diet considers calorie intake, fats, protein, carbohydrates, vitamins and minerals. Getting it right can improve quality of life, muscle function and bone health.

How much energy does a person with SMA need?

Dieticians usually estimate that people with SMA need 20 to 50% fewer calories than others of the same age, because they move less and use less energy. Even small increases in calories can cause significant weight gain.

A nutritionist can help you find the right balance of protein, fat and carbohydrate, recommend foods your child can manage more easily, and make sure they get enough vitamins and minerals. Many children with SMA are low in calcium and vitamin D — supplementing both may strengthen bones and help prevent fractures.

Common nutrition problems in SMA

Feeding and swallowing difficulties

Depending on the type and severity of SMA, children may have difficulty chewing or swallowing, and may choke. Causes include limited mouth opening, weak tongue and facial muscles, poor head control and tiredness of the chewing muscles.

What helps: a semi-solid diet and thickened liquids; good positioning and supportive seating; orthotic devices that help people eat on their own and swallow more safely.

Aspiration

Small amounts of food, liquid or stomach contents enter the windpipe instead of the food pipe. This can cause pneumonia and difficulty breathing.

What helps: some people with SMA are advised a nasogastric tube (a feeding tube through the nose into the stomach) or a gastrostomy tube (a tube placed through the skin directly into the stomach). These make feeding safer and allow more nutrition to be given. See also breathing.

Reflux (GERD)

Most common in Type 1, followed by Type 2. Scoliosis can increase pressure on the abdomen and make reflux worse, and constipation can worsen reflux and breathing symptoms. Reflux increases the risk of aspiration and causes pain.

What helps: small, frequent meals; avoiding foods that irritate; medicines to neutralise or reduce stomach acid, as advised by your doctor.

Tummy discomfort

Diarrhoea, bloating, spitting up, vomiting after meals, bad breath and a swollen tummy are common and can contribute to undernutrition. Tell your doctor if they happen often.

Constipation

Infrequent bowel movements are linked to slow gut movement, low fibre and not enough fluids.

What helps: high-fibre foods, enough water, and probiotics. Your doctor may recommend a laxative.

Undernutrition

Difficulty growing and gaining weight is common in Type 1 and sometimes in Type 2. It increases the risk of infection, slow wound healing and pressure sores.

What helps: nutritional supplements, and early involvement of a dietician if a baby is significantly underweight.

Overweight

More common in milder Type 2 and Type 3. Extra weight increases pain and problems with hips and back, makes caring and transfers harder, and raises the risk of diabetes and high blood pressure. Calorie needs can be as low as half of what another child of the same age needs.

What helps: a dietician-led plan, and physiotherapy to stay as active as possible.

A checklist for families

• Track your child’s weight and height on a growth chart.
• Agree a personalised feeding plan with your medical team.
• Report choking, coughing during meals, reflux or constipation early.
• Ask about calcium and vitamin D.
• Plan ahead for what to do with feeding when your child is unwell.

See also the dietary section of our COVID-19 guidelines, which includes practical tips on reflux and avoiding aspiration.