Overview
Protein is a nutrient made of building blocks called amino acids. Your body uses it for growth, tissue repair, muscle maintenance, and many basic functions such as making enzymes and hormones. Protein is found in foods like beans, lentils, peas, soy foods, nuts, seeds, dairy foods, eggs, fish, and meat.
Causes and Risk Factors
People may not get enough protein if they do not eat enough food overall, have limited access to a variety of foods, or follow a very restricted eating pattern without planning. Higher needs can happen during growth, pregnancy, breastfeeding, recovery from illness or injury, and older age. Some health conditions can also affect how the body digests, absorbs, or uses protein.
Who Is Affected
Everyone needs protein, but needs vary by age, body size, life stage, activity level, and health status. Children and teenagers need protein to support growth, while older adults may need careful meal planning to help maintain muscle. People who eat mostly plant-based diets can meet their needs, but they may need to include a range of protein-rich foods regularly.
Prevention
A balanced eating pattern with regular sources of protein can help prevent low intake. Including protein foods across the day, rather than in only one meal, may make it easier to meet needs. If food choices are limited by cost, culture, allergies, or appetite, a doctor or dietitian can help identify practical options.
Diagnosis and Tests
Protein intake is usually assessed by asking about eating habits, weight changes, and overall health. A healthcare professional may look for signs of poor nutrition or muscle loss and may use blood or urine tests in some situations, depending on the concern. There is not one single routine test that fully reflects everyday protein intake for everyone.
Diet and Lifestyle
Good protein sources include beans, lentils, peas, tofu, tempeh, nuts, seeds, dairy foods, eggs, fish, poultry, and lean meats. Choosing a mix of protein foods can also provide other nutrients such as iron, zinc, vitamin B12, calcium, and fiber. It can help to pair protein foods with vegetables, fruits, whole grains, and healthy fats as part of overall meal planning.
When to Seek Medical Care
Seek medical care if there is ongoing unintentional weight loss, poor growth in a child, trouble eating, frequent vomiting or diarrhea, or concern about malnutrition. Medical advice is also important for people with kidney disease, liver disease, eating disorders, or other conditions that may affect protein needs. A healthcare professional can help assess whether symptoms are related to diet or another health problem.
Questions to Ask a Healthcare Professional
You may want to ask whether you are likely getting enough protein for your age, health, and activity level. Other useful questions include which foods fit your culture, budget, or dietary pattern, and whether a medical condition changes your nutrition needs. If you are considering supplements, ask whether they are appropriate for you and how they may affect other parts of your diet.