by Ashleigh Feltham,  Accredited Practising Dietitian and Accredited Nutritionist

The process of digestion and absorption of the food you eat is quite complex. There are many factors and processes that allow you to take in nutrients from your food. Research on the gut microbiome continues to grow, and new findings show there is an increase in mineral absorption when prebiotics and minerals are ingested together.

Your gut microbiome is unique to you and is made up of a variety of microbes. Many factors influence the types of microbes that live in your gut. One major factor is diet. Health-promoting microbes love plant foods, which contain a variety of prebiotic fibre.

Prebiotics are a type of carbohydrate that the body cannot digest. It is, however, a favourite food for health-promoting microbes living in your gut. When these microbes consume prebiotic fibre, they create messages that provide health benefits to your body. One of these health benefits is increasing the ability to absorb minerals.

The minerals linked to increased absorptive capacity when combined with prebiotics are calcium, magnesium, and iron. All three of these minerals play an important role in your body.

Calcium is needed to help keep your bones and teeth strong. It is also necessary for normal muscle contractions.

Magnesium is an essential mineral involved in over 325 different body functions. Magnesium supports bone health, promotes healthy blood pressure, helps turn food into energy, supports good sleep, and helps reduce stress.

Iron is an important part of haemoglobin, the protein in red blood cells. Haemoglobin binds to oxygen and carries it throughout the body, and every cell needs oxygen to survive. Iron also promotes an optimal immune system.

Specific types of prebiotics linked to improved mineral absorption include lactulose, inulin and oligofructose, also known as transgalacto-oligosaccharides (TOS). These probiotics play an essential role during adolescence when peak bone mass is being created and for postmenopausal women to minimise bone loss.

These prebiotics also increase the absorption of magnesium and calcium. This combination is beneficial for many functions, such as bone health. Including these prebiotics with calcium and magnesium food sources is both a sustainable and cost-effective way to promote better bone health throughout life.

Inulin and oligofructose are also linked to the increased absorption of iron. This link is important, considering that an estimated one-quarter of the world’s population suffers from anaemia. In addition, a number of factors inhibit the animal source of iron, called non-haem. Having a strategy to promote an increase in iron absorption is of benefit to many people, especially those who follow a purely plant-based diet.

It is hypothesised that the prebiotic-microbe interaction increases mineral absorption in several ways. This includes microbes producing short-chain fatty acids, which can play many roles in promoting metabolism in the gut including the absorption of minerals.

Health-promoting microbes also secrete compounds that optimise the pH of the intestine, supporting the absorption of minerals. They allow biomarker modification and the creation of homeostasis and optimal immune system function. These factors all create an environment in the gut that allows mineral absorption to a greater extent.

Many different plant-based foods are sources of prebiotic fibre. These include wholegrains, nuts, seeds, legumes, vegetables and fruit. Look out for foods containing added inulin, a prebiotic fibre.

Take home message:

There are several factors that promote greater mineral absorption. A cost-effective strategy is to include prebiotics, inulin and oligofructose, with every meal to help maximise the absorption of calcium, magnesium and iron.

References:

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