Can I Get All My Nutrients from Food?

I was recently presented with the question, "Can I get all my nutrients from food or are vitamins essential?".

The simple or not so simple answer is yes, it is possible to obtain all nutrients from food, if you know the exact needs of your body and precisely how well you absorb those nutrients. If that information is known, then you can consume foods throughout the day to obtain 100% of your needed nutrients.

Is this a simple answer? Absolutely not. Testing how well your body absorbs nutrients is not commonly done, nor does this test demonstrate how effective your body is at utilizing those nutrients once they are absorbed.

Is it possible to obtain the recommended daily allowance, or RDA, of nutrients put in place by the National Academy of Medicine? The answer is yes. The RDA values are known to be the amount of nutrients, vitamins and minerals, that are adequate for meeting a general healthy individual's nutritional needs. This can be done by eating a balanced variety of foods such as whole grains, vegetables, fruit, nuts, seeds, and animal based foods in moderation.

This is a complicated topic. Just because a person gets 100% of their RDA of vitamins and minerals does not mean their body absorbs and uses 100% of the consumed amount. In fact, your body does not absorb 100% of nutrients you consume. This statement stands true for nutrients obtained from food and supplements such as a multivitamin.

There are many factors that impact the absorption of nutrients such as location of absorption, nutrients consumed at the same time, bioavailability, and anti-nutrient content.

Where Absorption Takes Place

Absorption of most nutrients takes place in the small and large intestines. If a person has an injury or inflammation in their intestines, such as celiac disease, irritable bowel syndrome, chronic diarrhea, ulcers, diverticulitis, diverticulosis, etc., then absorption of nutrients is not as efficient as it would under healthy conditions.

Bioavailability

Depending on the food source the nutrient comes from, absorption may be easier or harder. When a nutrient is bioavailable, it means it is in a form that is available or ready for your body to absorb and use. Some foods contain nutrients that have lower bioavailability than others. Animal meats tend to have nutrients that are more bioavailable than plant foods.

Competition and Assistance

Some vitamins and minerals, when consumed together, help each other get absorbed. Vitamin-C and non-heme iron, or iron from plant-based foods that is not readily available to be absorbed, are good examples of a pair of nutrients that help each other out. When Vitamin-C is consumed with iron-containing food, absorption of iron increases.

Anti-Nutrients

Some foods contain compounds referred to as anti-nutrients. These compounds block nutrient absorption in the body by binding to them in food. Some examples of these are phytates, tannins, oxalates, and lectins to name a few. These compounds are found in plant foods such as nuts, seeds, legumes, tea, coffee, whole grains and vegetables.

Phytates bind to certain minerals within foods. Phytase is an enzyme that is responsible for breaking down phytic acid (phytates) to allow for the nutrient it is attached on, to become free and able to be absorbed. Phytase is not made within the human body, it is present in some plants as well as bacteria and yeast. Some methods of food preparation can break down or pull phytates out of foods. Phytates are water soluble and when foods are soaked or sprouted, phytates are pulled into the water and out of the food. Soaking beans, legumes, nuts, and seeds before consuming them can make them easier to digest and makes nutrients more available.

Tannins are often referred to as an antinutrient because of their ability to decrease or inhibit the absorption of iron. Oxalates are compounds that bind to calcium and sometimes iron in the body. In large amounts, oxalates can cause kidney stones to develop. Lectins are compounds that can bind to some carbohydrates and prevent the body from absorbing them as a nutrient source.

There are many factors that influence the absorption of nutrients. Taking a nutrient supplement is helpful for certain individuals. It is important to keep in mind that many supplements contain over 100% of a persons daily needs and when all nutrients are together in one vitamin, certain ones can compete or block absorption of others. Most healthy individuals can obtain their needed amount of nutrients through eating a balanced diet with a variety of fruits, vegetables, nuts, seeds and animal based foods.