Because chronic obstructive pulmonary disease patients often struggle to breathe — and that struggle requires a lot of energy — weight loss and malnutrition can be side effects of the disease. Particularly in the later stages of the disease, weight loss resulting from a condition called pulmonary cachexia can signal poor prognosis.

Pulmonary cachexia is a muscle wasting syndrome that leaves patients weak and unable to function normally. It happens because the energy required by the body to breathe and complete everyday tasks is so great, it can’t be adequately addressed by normal dietary means. The result is unintended weight loss that can lead to malnutrition. According to a 2015 review study conducted in Taiwan, “overall, 10 to 45 percent of patients with COPD are malnourished, and it is evident that malnutrition and undernutrition are important prognostic factors for COPD patients.”

[See: 8 Surprising Facts About Asthma and Seasonal Allergies.]

For patients with advanced lung disease or pulmonary cachexia, dietary supplementation can address issues of malnutrition and help you regain some of the weight you’ve lost. “In terms of the really underweight patients, oral nutritional supplements can help because it’s hard for them to eat enough,” says Michelle MacDonald, clinical dietitian at National Jewish Health in Denver. Patients with advanced disease may have a decreased appetite, “and they can’t eat a lot at one time,” because “in some cases people with emphysema have hyper-inflated lungs that are taking up a larger volume in the body. This pushes down on the stomach and makes it so they can’t eat as much.” If this is what’s happening with you, your doctor may recommend a liquid dietary supplement.

This is the flip side of the obesity counseling that many Americans may have received from their doctors at one point or another. While many people are urged to drop high-calorie beverages from their diets as an easy means of cutting calories to lose weight, adding high-calorie drinks to the diet can be a lifeline for some COPD patients for the very same reason. Drinking your calories — as long as they’re nutritious — can be a fast and efficient way to get the nutrients and energy you need.

MacDonald says “it doesn’t have to be the leading brand,” and virtually any drinkable meal replacement shake can do the trick. She says patients can also blend their own drinks at home, such as a smoothie with protein powder or other calorie sources added in to taste. “We can really concentrate these shakes and they’re digested more quickly, so it’s not so much effort to eat,” but can help people with severe lung disease get the nutrients their bodies need, MacDonald says. She recommends speaking with a dietitian to determine the best liquid supplement for your specific situation. Most pulmonary rehabilitation programs include nutritional counseling that should help you determine the best approach for your individual circumstance.

No matter which liquid supplement you select, the 2015 study reports, “it is important to provide nutrition that has high calorie density. This will also help to minimize abdominal distention that may cause discomfort while eating.” The whole point of these nutritional supplements is to increase the number of calories you’re taking in to help offset the calories you’re burning to breathe, but to do so with nutrient dense foods, such as fruit, vegetables and high quality protein powders or fat sources.

[See: 7 Lifestyle Tips to Manage Your Asthma.]

COPD patients are also advised to select nutritional supplements that contain more fat than carbohydrates, according to that 2015 study. “It has been proposed that increasing the calorie intake of COPD patients through a higher fat content diet may be more beneficial,” because fat produces less carbon dioxide in the body “and has a lower respiratory quotient compared with carbohydrate metabolism. This may be particularly important in COPD patients with hypercapnia [elevated levels of carbon dioxide in the blood] and those suffering from shortness of breath.” For a translation, Dr. Katina Nicolacakis, staff pulmonologist at Cleveland Clinic, says, “The more carbs you eat, these get converted to carbon dioxide [during digestion] and then you need to breathe more,” to expel that carbon dioxide. “In general, I think we should all eat less carbs, but definitely people with COPD need to eat less carbs,” she says. Therefore, liquid supplements that are high in fat and protein are generally preferable for underweight COPD patients than sugary supplements that are high in carbohydrates.

In addition to adding calories to your diet, there is some evidence that boosting the level of certain vitamins and minerals in the diet or taking vitamin supplements may be helpful for some COPD patients. A 2012 study published in the Journal of Nutritional Biochemistry found an association between intake of omega-3 and omega-6 fatty acids and a reduction in inflammation in COPD patients, which suggests that increasing the intake of these fatty acids in the diet or via supplementation could be helpful. Fish, nuts, vegetable oils, flax seeds and leafy vegetables are all good sources of omega-3 and omega-6 fatty acids.

Similarly, several small studies have noted that supplementation with amino acids — the building blocks of protein — could also help improve prognosis for patients with severe COPD. Supplementation with antioxidants and vitamin D has also been associated with symptom relief in some patients with severe COPD. Dietary sources of antioxidants include many brightly colored fruits (berries, in particular, are high in these oxidative-stress fighting compounds) and dark green leafy vegetables. Vitamin D is the only vitamin humans can manufacture — sunlight on the skin produces it naturally in the body — but too much sun exposure can put you at risk for sunburn and skin cancer, so dietary sources of this important nutrient that helps your body absorb calcium to keep your bones strong are dairy products, salmon and fortified cereals.

[See: 7 Things You Didn’t Know About Lung Cancer.]

Although some doctors say that pill supplements aren’t worth the money or the potential risks, speak with your doctor about your prognosis and whether you should add a vitamin pill, dietary supplement or begin using liquid nutritional supplements. In some instances, they may be helpful to reduce severity of symptoms, reduce your risk of exacerbations or improve your quality of life.

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Should I Use Dietary Supplements for My COPD? originally appeared on usnews.com