Micronutrient Deficiencies Start in the Gut: 3 Functional Nutrition Tips for Better Absorption
Micronutrient deficiencies are much more common than you may expect. We’ve all heard the saying “you are what you eat,” but in reality, you are what you digest and absorb. You can eat a diet rich in vitamins and minerals, but if your gut isn’t functioning properly, much of that nutrition never makes it into your cells.
The gut is the true gateway to micronutrient absorption. Micronutrients are vitamins and minerals, which power everything from hormone production to energy metabolism. Of course, these essential nutrients only work if they’re absorbed. When gut health is compromised and digestion is impaired, deficiencies can appear despite an otherwise healthy diet.
The Roles of Stomach Acid and Bile for Unlocking Micronutrients
Stomach acid is a critical and often overlooked factor of nutrient absorption. Also known as hydrochloric acid (HCl), stomach acid is essential for breaking down food-bound minerals into available forms. Without sufficient acid, minerals like iron, zinc, and calcium remain locked in food particles, unable to absorb into the bloodstream.
Low stomach acid, or hypochlorhydria, is surprisingly common. Signs include bloating, excessive burping, early fullness, undigested food in stool, even low B vitamins and iron levels. Frequent use of acid-blocking medications such as proton pump inhibitors (PPIs) contributes to the problem by suppressing stomach acid long-term, setting the stage for mineral imbalances.
Bile is another equally important key player in digestion. Bile is produced by the liver and stored in the gallbladder. It is released into the intestines to break down fats so that fat-soluble vitamins (A, D, E, K) and fat-soluble minerals like calcium and magnesium can be absorbed. Poor bile flow contributes to constipation, sluggish digestion, and gut dysbiosis – all of which further promote poor gut health and nutrient absorption. Impaired bile flow can even decrease thyroid function, slow liver detoxification, and impact hormone balance.
When we lack sufficient pancreatic digestive enzymes, both fat and protein digestion take a hit. Not being able to break food down into small enough particles inhibits the ability to unlock vitamins and minerals from foods. In addition to micronutrient deficiencies, this can also cause significant GI discomfort and gut inflammation. Over time, this can lead to food sensitivities given the chronic immune response triggered by the gut immune system.
Boost the Gut Microbiome to Support Nutrient Absorption
The microorganisms in your gut that make up your gut microbiome play a direct role in micronutrient bioavailability. Certain microbes even produce nutrients themselves, such as vitamin K, certain B vitamins, and thyroid-supportive minerals like selenium. Others influence magnesium balance or indirectly support nutrient absorption by reducing inflammation in the gut lining.
Beneficial bacteria ferment the prebiotic fibers in your diet, turning them into short-chain fatty acids (SCFAs) like butyrate, acetate, and propionate. These are anti-inflammatory compounds that improve mineral absorption and transport out of the gut, and maintain the integrity of the gut lining.
Prebiotic fibers, such as those found in onions, garlic, asparagus, and Jerusalem artichokes, not only serve as fuel for SCFA-producing microbes, but they themselves are also mineral-rich food sources.
In addition to the gut microbiome, the integrity of your gut lining is another key piece of overall gut health. If that lining is weak, it can become permeable, leading to what’s considered “leaky gut.” This can further drive gut dysbiosis, inflammation, and impaired micronutrient absorption.
Nutrition and Lifestyle Factors that Get in the Way of Healing
Even with a balanced diet, several common disruptors can sabotage gut healing and nutrient replenishment. Collectively, high cortisol, acid-blocking medications, and antibiotics can contribute to leaky gut, low stomach acid, and an imbalanced gut microbiome.
Chronic stress and high cortisol shift the body into “fight or flight” mode, downregulating digestion. In this state, stomach acid production declines and microbiome diversity suffers. Acid-blocking medications, including antacids, H2 blockers, and PPIs, may be useful short-term if necessary, but long-term use impairs digestion and vitamin and mineral availability.
It’s no secret that antibiotics don’t only target harmful bacteria, but they also clear out beneficial bacteria that help liberate nutrients and even produce vitamins and anti-inflammatory SCFA compounds in the gut. This microbiome disruption can open the door to overgrowth of resistant bacterial strains and even fungi such as Candida.
Certain dietary compounds can also interfere with mineral absorption. Phytates, found in oats, legumes, and nuts, and can bind minerals like iron and zinc, making them harder to absorb. Oxalates, concentrated in spinach, almonds, and beet greens, bind calcium and magnesium. Additionally, some minerals compete with one another for absorption, such as calcium and iron. Even supplement binders like activated charcoal can deplete essential micronutrients, especially if used long-term without proper replenishment.
Finally, modern agriculture adds another layer to the micronutrient deficiency conversation. Due to soil depletion, our crops today contain far fewer vitamins and minerals than they did 50 years ago, making our food a less reliable source of essential micronutrients.
Top 3 Functional Nutrition Strategies to Restore Gut Health for Better Nutrient Absorption
So how do you break the cycle and restore nutrient balance? Functional nutrition starts with the gut, and the following foundational strategies which can be built upon.
- Support stomach acid production and bile flow
Eat slowly and chew thoroughly to stimulate digestive juices. Lemon water or a splash of apple cider vinegar before meals can prime digestion and kick start stomach acid production. Incorporate bitter foods like arugula, dandelion greens, citrus, and radicchio before meals to stimulate bile flow. Additionally, don’t shy away from healthy fats like cold-pressed extra virgin olive oil and avocado, as these help stimulate bile production and improve fat-soluble vitamin absorption. - Feed the microbiome
Include a variety of prebiotic fibers such as onions, garlic, and artichoke, as well as probiotic-rich foods like sauerkraut, kimchi, tempeh, and kefir. Together, these support SCFA production and restore microbial diversity for better micronutrient uptake. Consider advanced stool testing for a deeper look into your gut microbiome. - Reduce mineral-blocking foods
Reduce phytates from your legumes by soaking and pressure cooking them, or purchasing a brand like Eden’s, which does this as part of their canning process. Opt for lower oxalate nuts and leafy greens such as walnuts and Brazil nuts, and spring mix or arugula. If supplementing with minerals, avoid taking iron with calcium-rich foods, especially dairy products.
Searching for More Functional Nutrition Strategies to Boost Gut Health and Replenish Minerals?
Micronutrient deficiencies rarely come down to diet alone. If your gut isn’t functioning well, whether due to low stomach acid, sluggish bile, or a disrupted microbiome, your cells won’t get the micronutrients they need to thrive. This can significantly impact your hormone balance and thyroid function.
In our Functional Thyroid Foundations group program (formerly Inflammation Hormony), we provide a functional nutrition plan with practical tools and strategies to support gut health and decrease inflammation, all for better nutrient absorption and thyroid function. Join the waitlist today as we countdown our next live program beginning August 25th!
Written by Romana Brennan, MS, RDN
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