What is the bioavailability of nutrients in beef?

Bioavailability is the proportion of an ingested nutrient that becomes available to be absorbed and used by the body. Therefore, the concept takes into account more than the amount shown in an food’s nutritional composition.

In the case of proteins, for example, how well they are used depends on digestibility and the amount of essential amino acids available. For minerals, the chemical structure and the presence of components that either promote or hinder absorption also play a role.

Beef provides complete proteins, heme iron, zinc and vitamin B12 in the same food matrix. My Minerva addresses this combination in the article 10 ways to maximize the benefits of beef in everyday life.

However, good bioavailability does not mean complete absorption. Age, nutritional status, gastrointestinal health and interactions with other foods also affect the outcome.

Why is the bioavailability of nutrients in meat important for health?

Bioavailability helps explain why the amount listed in a nutrition table does not necessarily correspond to the total the body uses. Two foods can provide the same amount of iron or zinc, for example, but differ in the form of the nutrient and in the presence of compounds that change its absorption.

In beef, proteins provide all essential amino acids and are highly digestible. Heme iron has greater bioavailability than non-heme iron found mainly in vegetables, while zinc from animal-based foods is less affected by phytates, natural substances found in foods such as grains, seeds, coffee and tea.

Vitamin B12 is also naturally present in meat, but its use requires a specific digestive process. First, gastric acid releases the vitamin from the food proteins. Then, it binds to intrinsic factor to be absorbed in the small intestine.

That is why nutritional quality involves both the presence of the nutrient and the individual’s ability to make use of it.

What does science say about the bioavailability of nutrients in beef?

The FAO, in its report on protein quality assessment, recommends considering the profile and digestibility of each essential amino acid. The DIAAS method assesses precisely how much of these amino acids is digested in the small intestine and becomes available to meet human needs.

Beef contains all essential amino acids and is highly digestible. These characteristics explain its classification as a source of high biological value protein, a topic explored in more depth by My Minerva in the article on the quality and digestibility of red meat protein.

Regarding iron, the National Institutes of Health explains that heme iron from meat is more bioavailable than non-heme iron. In addition, meat, poultry and seafood can help the body use the non-heme iron consumed in the same meal.

The NIH technical fact sheet on zinc also notes that the bioavailability of the mineral in meat and other animal-based foods is higher than in many plant sources. This is because grains, legumes and seeds may contain phytates, which bind to zinc and reduce its absorption.

Vitamin B12, in turn, depends on digestive health. Even if meat provides the nutrient, changes in gastric acid or intrinsic factor production can limit its use. The process is detailed in My Minerva’s article Meat is one of the few natural sources of B12.

Who benefits from consuming nutrients with good bioavailability?

Bioavailable nutrients are important at every stage of life. However, children and adolescents go through periods of growth, while pregnant women have increased needs for protein, iron and other micronutrients.

Women of childbearing age also need to pay attention to iron intake because of menstrual losses. Among older adults, protein quality becomes especially relevant for maintaining muscle mass, while digestive changes can compromise the use of vitamin B12.

People with restrictive diets, low food intake or increased nutritional needs may also benefit from concentrated sources of nutrients. My Minerva explains these situations in the article The importance of meat for women, pregnant women, children and older adults.

However, high bioavailability does not replace medical or nutritional assessment. Gastrointestinal diseases, surgeries, medication use and existing deficiencies may require specific strategies.

How can you better use the nutrients in beef in your diet?

Beef can be part of meals with rice, beans, vegetables and greens, making up a varied and balanced diet, since this combination brings together protein, fiber, vitamins and minerals.

Including meat in a meal may also help the body use the non-heme iron found in beans and vegetables. In addition, foods rich in vitamin C, such as tomatoes, peppers, oranges and broccoli, promote the absorption of this form of iron.

Varying cuts and using roasted, boiled, stewed or grilled preparations helps adapt beef to different meals. However, there is no method that can guarantee complete use of all nutrients.

It is also important to respect portions and consider the overall diet. Bioavailability does not turn a single food into a solution for all nutritional needs.

Myths and facts about the bioavailability of nutrients in meat

The amount of a nutrient determines how much will be used

Myth. The amount present in the food is only one factor. Chemical form, digestibility, meal composition and individual conditions also influence absorption and use.

Beef protein is well used by the body

Fact. Meat provides all essential amino acids and is highly digestible. The FAO recommends that these two criteria be considered when assessing protein quality. 

The iron in beef has greater bioavailability

Fact. Heme iron found in meat is more bioavailable than the non-heme iron commonly found in plant foods. This does not mean, however, that plant sources do not contribute to mineral intake.

All zinc in foods is absorbed in the same way

Myth. Absorption varies according to the source and the composition of the diet. However, phytates in some vegetables can reduce zinc use.

Eating meat guarantees adequate vitamin B12 absorption

Myth. Meat is a natural source of B12, but absorption depends on gastric acid, intrinsic factor and intestinal function. People with digestive changes may develop deficiencies even when they consume animal-based foods.

High bioavailability means all of the nutrient will be absorbed

Myth. No food guarantees complete use. The amount absorbed varies according to the dose, nutritional status and each person’s characteristics.