What you eat can have a tremendous impact on your health. Proper diet and nutrition are not only important for overall health, but they can also change how your mind and body deal with disease. Dietary changes can have a significant impact on medical conditions like type 2 diabetes and high blood pressure, but other chronic conditions are also greatly affected by what you put into your body. For example, spinal muscular atrophy (SMA) is one of these conditions.

SMA is a neuromuscular disorder, which means it affects both nerves and muscles. It attacks the motor neurons, the nerves that send signals for movement to the muscles, leading to muscle weakness and atrophy (shrinkage). Recent research has found that SMA also affects how the whole body breaks down or metabolizes fatty acids. Abnormal fatty acid metabolism can lead to nutritional deficiencies, which can cause many physical problems in people with SMA.

What Are Fatty Acids?

Fat is a nutrient, along with protein, carbohydrates, vitamins, and minerals. Nutrients are the substances that our bodies need to function that come from what we eat and drink. A healthy diet is made up of all of these nutrients in the proper amounts to meet the body’s needs.

Fats in our diet come from eating plants and animals and include oils extracted from vegetables like corn. Fat has about twice the calories of protein and carbohydrates, meaning that you have to eat less of it to get the same number of calories as protein and carbohydrates. All fats are made up of fatty acids, which are molecules that consist of a chain of carbon atoms with a group of carbon, oxygen, and hydrogen atoms (carboxyl group) at one end. They are generally described by the length of their chain (e.g., medium-chain fatty acids) and whether they are saturated or unsaturated. In the body, fatty acids are used to build cells and store and produce energy. Essential fatty acids (such as omega-3 and omega-6 fatty acids) cannot be made by the human body alone and must be obtained from the diet.

SMA and Fatty Acids

Research has shown that people with SMA have impaired fatty acid metabolism, or the inability to properly break down fats so they can be used and stored by the body:

• Mutations in the survival motor neuron 1 (SMN1) gene cause most types of SMA (SMA type 0 to type 4) by preventing the production of functioning SMN protein.
• Lack of SMN protein not only affects motor neurons (the nerve cells that connect to muscles), but also has other effects.
• People with SMA have difficulty breaking down long-chain fatty acids into fatty acids that can be used to produce energy. This leads to excess fat storage in the body (increased body fat) and other problems, such as low fasting blood glucose (low blood sugar).

SMA can cause lower-than-normal body weight in infants and children and can also alter their body’s balance of fat and muscle, tending to produce muscle loss and fat buildup. Body mass index (BMI) is a tool that is sometimes used in the medical community to classify a person’s height-to-weight ratio as underweight, normal, or overweight.

BMI values, however, are not accurate in people with SMA. SMA alters body composition and height, causing a significant loss of lean body mass (from muscle wasting) and an increase in body fat. This means that a normal BMI in someone with SMA can be a sign of being overweight. Being either overweight or underweight can worsen SMA symptoms, like difficulty breathing and moving.

The Latest Research

Several different researchers have compared the effects of a low-fat versus a high-fat diet in mice with SMA and found interesting results. Using genetically engineered mice with SMA, researchers compared the effects of lower and higher dietary fat content on health. Although the results of these studies are difficult to compare based on significant differences in methods, SMA mice tended to have better outcomes with diets that contained less fat as opposed to more fat. Research into the effect of diet on SMA mice has many serious limitations and shortcomings that make it difficult to apply to humans. Still, some of the evidence supports what many people with SMA have found — that eating less fat can improve select symptoms of SMA.

Diets for SMA

There is no research that shows exactly what amount of fat in the diet is beneficial for SMA:

• The FDA generally recommends eating 78 grams of fat per day for a 2,000-calorie-per-day diet (fat would make up 35 percent of calories consumed).
• People with SMA all have different calorie requirements, depending on their age, body size, mobility, and more.
• Fats that are consumed should consist mostly of polyunsaturated fats.
• Polyunsaturated fats are typically liquid at room temperature and come from plants.

One example of a good source of unsaturated fat is olive oil. On the other hand, saturated and monounsaturated fats should be eaten in moderation. Saturated fats are usually solid at room temperature and are found in meat and dairy products, such as butter.

There is no specific diet that is recommended for SMA, but people have tried a variety of dietary changes that they say help with their symptoms, such as respiratory difficulty. Elemental diets, such as the amino acid diet, are popular among some people with SMA who report that they see symptomatic improvement. The amino acid diet is reported to have helped some children improve gastrointestinal problems and reduce respiratory secretions after having difficulty digesting fat and protein in dairy and soy-based formulas.

Nutrition for SMA

People with SMA may require dietary modifications to provide proper nutrition and avoid eating-related problems such as acid reflux and aspiration (inhaling food or fluid into the lungs):

• Due to low muscle mass and limited mobility, people with SMA usually require fewer calories in their diet.
• Reducing caloric intake can help lower body fat and excess weight. However, reducing the number of calories can also reduce the intake of other nutrients.

Vitamin deficiency is common in SMA, especially with the vitamins A, D, E, and K because they require fat to be absorbed. Vitamin D (and calcium) are critical for bone health in people with SMA, who are often at risk for bone-related problems like osteoporosis and fractures. Ask your health care provider about checking blood levels of key vitamins and minerals and how to supplement any deficiencies you may have.

People with SMA should keep track of the calories they eat to maintain appropriate body weight and composition (the balance of muscle and fat). Monitoring caloric intake is important, but so is making sure that you are getting calories from a balance of protein, carbohydrates, and fat.

People with severe SMA that affects the muscles for chewing and swallowing usually require additional nutrition given through a feeding tube (also called a G-tube or PEG tube). Feeding tubes have their own set of considerations, but they do allow for exact monitoring of the nutrients given to a person to supplement their diet or replace eating by mouth entirely. They also allow people with SMA to preserve the energy they would have spent chewing their food for other activities.

Eating a variety of foods and whole grains can provide healthy sources of nutrients:

• Fruits
• Vegetables
• Lean protein
• Unsaturated fats

Processed foods and simple sugars can provide you with the calories you need, but often without the benefit of vitamins and dietary fiber. Treats are fine too — just remember to enjoy in moderation!

Changing How and What You Eat

Before making significant changes in your diet, always consult with a dietitian or qualified health care provider who has experience with SMA. They will make sure that a new diet will meet your nutritional needs.

In addition to changing what you eat, changing how you eat can ease certain symptoms that arise from SMA:

• Soft foods and thickened fluids may be recommended for people who have dysphagia (difficulty chewing and swallowing).
• Some people are at high risk for aspiration (food entering the lungs) due to swallowing muscle weakness and should not take food and drink by mouth.
• People with SMA should avoid large meals and eat smaller, more frequent meals throughout the day.
• Eating smaller amounts can help avoid gastrointestinal symptoms and acid reflux.
• Other ways to help prevent acid reflux include eating a low-fat diet, not lying down after eating, and avoiding fatty or greasy foods, spicy foods, chocolate, and acidic foods.

Many people with SMA benefit from a specially tailored diet. If weight loss is required, reducing calories, reducing fat, and making sure that you are getting enough vitamins and minerals can help. Stricter diets that tightly restrict what you eat can help some people achieve significant improvement of quality of life with SMA. Always approach changes in diet with caution if you have a chronic illness, especially if it is a disorder that affects metabolism, like SMA.

What is healthy for other people might not be healthy for you. Check with a dietitian or another provider who has experience in nutrition for people with SMA to find what dietary changes are best for you.

Talk With Others Who Understand

On mySMAteam, the social network for people with spinal muscular atrophy, more than 1,200 members come together to ask questions, give advice, and share their stories with others who understand life with SMA.

Are you or someone you care for living with spinal muscular atrophy? Share your experience in the comments below, or start a conversation by posting on your Activities page.