Minerals: We are what we absorb
Introduction
We are what we eat? Well, “we are what we absorb” might be the more precise statement. It is possible to eat enough to meet the recommended nutritional needs on paper, but if your body is not absorbing those nutrients, then it is simply not enough nourishment, and the risk of malnutrition is high. Those living with a compromised gut, from such conditions as Crohn’s disease, short bowel syndrome, and celiac disease require additional minerals compared to a healthy adult.
You can meet these increased needs with the help of dietary counselling and ongoing monitoring and assessment by your healthcare team. This includes nutritionally-focused physical exams, which are key to prevent the consequences of micronutrient deficiencies, such as anemia, fatigue, weakness, and decreased immune function. This article will focus on common mineral deficiencies associated with a compromised gut, practical tips to enhance absorption, and general recommendations for the prevention and treatment of these deficiencies.
Crohn’s Disease
Malabsorption in Crohn’s disease varies for each person and depends on the disease location, degree of inflammation, past surgeries (including intestinal resection), severity of diarrhea, and/or having an ostomy or high output fistula (>500 ml/d). There will be less absorption during a flareup when there is inflammation, and more during remission when there is minimal to no inflammation present. Common mineral deficiencies in Crohn’s disease include iron, zinc, magnesium, and calcium.1 If you have high output fistulas, you will also have increased needs for copper, zinc, and selenium to promote wound healing.2
Short Bowel Syndrome
Short bowel syndrome (SBS) is a condition in which there is a significant loss in the length and/or function of the small intestine, typically 70-75% loss of the small intestine,3 resulting in severe malabsorption. More than 90% of nutrient absorption occurs in the first 100-150 cm of the small intestine (duodenum and jejunum), so if this area of your intestine is missing or not functioning well, then the risk of malnutrition is extremely high. SBS can arise from massive surgical resection, Crohn’s disease, cancer, radiation enteritis, injury, or other, less common reasons. A person who has SBS will need nutritional support (e.g., tube feeding, or IV feeding called TPN) in the short- or long-term. Mineral deficiencies of specific concern include magnesium, zinc, iron, calcium, and selenium, along with vitamins A, D, E, K, and B12.3 A person living with SBS will require lifelong monitoring and supplementation of these nutrients.
Celiac Disease
Celiac disease is an autoimmune disease that primarily affects the small intestine, which is where your body absorbs most of the nutrients from the food you eat. The treatment for this disease is a strict and lifelong gluten-free diet to prevent intestinal inflammation and consequent malabsorption resulting from exposure to gluten. Iron deficiency and iron deficiency anemia are both quite common in celiac disease.4 Sometimes your physician might first realize you might have celiac disease if you have anemia, osteopenia, or osteoporosis, because these can result from malabsorption of various minerals. Other mineral deficiencies that can occur in celiac disease include zinc, copper, magnesium, and selenium.
A 2020 study4 conducted on young patients with iron deficiency and celiac disease found that a gluten-free diet may be sufficient to reverse iron deficiency, but it can take between 6 months to a year to correct, and so additional supplementation and eating iron-rich foods on a gluten-free diet is recommended if iron levels are low. The researcher found that the general food choices made on a gluten-free diet in this age group were nutrient-poor, and that inadequate adherence to a balanced gluten-free diet also played a role in developing nutrient deficiencies.4 Cereal grains that have gluten also contain minerals such as copper and zinc, and so it is very important to substitute these with nutrient-dense gluten-free foods and grains such as quinoa and teff, instead of sticking to white rice and potatoes. Variety and balance are key!
Specific Deficiencies
Iron deficiency can occur due to malabsorption, decreased oral intake, and losses (e.g., bleeding), and you may require IV supplementation to correct this. We recommend regular monitoring of iron levels to prevent iron deficiency anemia, and eating iron-rich foods, and/or supplementation. This is especially necessary in Crohn’s disease, for those who consume a vegetarian or vegan diet, and for women during their reproductive years. (Ask for our pamphlet on Iron Deficiency Anemia.)
Zinc deficiency can occur when you have severe diarrhea, and when you have losses from a high output ostomy or fistula. Zinc is key to supporting the proper function of the immune system, promoting wound healing, and in the creation of protein and DNA.5 In Crohn’s disease, you could lose as much as 12 mg of zinc per 1 L of stool or effluent (ostomy output), and you will likely need further supplementation to replenish these losses. Be careful, though, as too much oral zinc supplementation can lead to copper deficiency over time, so limit supplementation to 6 weeks.
Magnesium deficiency can also occur due to malabsorption, reduced food intake, and excessive losses (diarrhea, high ostomy or fistula output), and in a compromised bowel. Oral magnesium supplementation, in general, can make diarrhea worse as it is typically not well absorbed; its primary use is as a laxative to prevent and treat constipation. Of note, there is a new form of oral magnesium called magnesium pidolate (Magdolate™), which could have increased bioavailability, meaning that it is easier for your body to absorb, so it won’t cause diarrhea like traditional magnesium supplementation. However, the majority of research comes from animal studies, and larger studies with humans are required to confirm this.6 Our bones store the majority of total body magnesium (60%), and chronically low magnesium levels can lead to bone disorders such as osteopenia and osteoporosis.3 Magnesium is key to maintaining good bone health, in addition to calcium and Vitamin D, so don’t forget about that magnesium!
Calcium deficiency can also occur due to malabsorption, reduced food intake, and increased needs with certain medications (e.g., steroids). It is easier for your body to absorb calcium supplementation in smaller, more frequent doses, typically two to three times per day. Calcium citrate is the best absorbed calcium for people with inflammatory bowel disease, and chewable forms do exist.3
Selenium deficiency can also occur due to malabsorption, reduced food intake, and excessive losses. Selenium is an essential mineral and a strong antioxidant that protects against oxidative damage in the body. It plays a key role in thyroid, muscle, and heart function, and helps to maintain and optimize a healthy immune system. Selenium occurs in high amounts in brazil nuts, seafood, kidney, and liver, as well as grains and legumes, although the selenium content in grains and legumes depends on the selenium content of the soil in which it’s grown. The recommended daily intake (RDA) for selenium is 55 mcg/day, and the tolerable upper-level limit is 400 mcg/day. It is possible to get too much selenium, and signs of selenium toxicity include nausea, diarrhea, hair loss, and nail changes. I would suggest no more than two brazil nuts per day to get plenty of selenium, while avoiding toxicity symptoms.
Conclusion
There is an increased risk of mineral deficiencies in compromised gut disorders, and the extent of this widely varies with each person. The good news is that you, with the support of your healthcare team, including your doctor, nurse, pharmacist, and registered dietitian, can monitor these mineral deficiencies. With a good dietary plan including targeted supplementation, you can prevent, or manage, nutrient deficiencies.
What you eat matters, but what your body absorbs matters even more.
Ten Practical Tips to Enhance Nutrient Absorption
- Chew very well until your food is the consistency of applesauce.
- Eat slowly.
- Consume solids and liquids about 30-60 minutes apart.
- Enjoy smaller, more frequent meals.
- Choose cooked vegetables instead of raw.
- Modify the texture of food (e.g., blended soups, blended oatmeal, smoothies, and mashed vegetables/fruit).
- Take calcium supplements in a divided dose (2-3X/day) and ask your doctor or pharmacist about calcium citrate.
- Eat more soluble fibre (e.g., oatmeal, bananas, applesauce) to help slow down intestinal transit time and allow more time for absorption.
- Drink coffee or caffeinated tea in between meals, as these decrease iron absorption of foods when taken with meals.
- Ask your doctor or dietitian about elemental formulas for episodes of severe malabsorption.
