Nutrient deficiencies in celiac disease diagnosis
Nutrient deficiencies in celiac disease diagnosis
The autoimmune disease celiac disease causes a flattening of the small intestinal lining over the course of the condition due to inflammation. This reduces the surface area through which the intestine can absorb nutrients from food. For many affected individuals, this leads to deficiencies in various vitamins and minerals. In this article, I will explain which nutrients you should pay particular attention to and which may need to be supplemented.
Which deficiencies are particularly common in a person with celiac disease when they are newly diagnosed?
The most common finding is an iron deficiency. This is also often the reason why celiac disease diagnostic testing is initiated in the first place. Iron is absorbed in the upper small intestine. The body needs iron to produce the red blood pigment (= hemoglobin, abbr. Hb). Many affected individuals are therefore identified through anemia when the iron deficiency is too pronounced. Since the red blood pigment transports oxygen from the lungs to the organs and tissues, a deficiency manifests itself through increased fatigue, headaches, pallor, and reduced physical performance. In very severe cases of anemia, shortness of breath and a racing heart also occur. To determine iron deficiency, the ferritin level should be examined. Free iron does not provide a good indication of the iron content in the body, as this value can fluctuate significantly throughout the day. Therefore, the iron level from the blood has little diagnostic value. A ferritin level that is too low indicates an iron deficiency. In addition, the hemoglobin level should naturally also be examined to see whether it is normal or already decreased. In the case of an iron deficiency, the red blood cells are also smaller than normal. Values that describe the red blood cells, such as the MCV, should therefore always be considered by your doctor, as this supports the suspicion of an iron deficiency. The MCV is the value for the mean corpuscular volume of the red blood cells and would therefore be smaller than normal in the case of an iron deficiency.
Anemia can also be caused by a deficiency in vitamin B12 and/or folic acid. These two vitamins may also be reduced in cases of newly discovered celiac disease. Therefore, they should always be checked when the diagnosis is initially made. Folic acid is necessary for cell division and therefore plays an important role, especially for pregnant women during the first weeks of pregnancy. In general, a deficiency can lead to depressive moods and increased irritability, in addition to the symptoms of anemia described above. Concentration problems have also been reported. A vitamin B12 deficiency can manifest in a similar way. Your doctor should examine the vitamin B12 level or holotranscobalamin, which is the active form of vitamin B12. This test is somewhat more accurate than the vitamin B12 value. To detect a folic acid deficiency, the blood level should be examined.
Another common vitamin deficiency at the time of a celiac disease diagnosis is a deficiency in vitamin D. This has serious consequences: regardless of age, 30-50% of newly diagnosed patients have reduced bone density. One contributing factor is that the inflamed mucous membrane makes it harder for the body to absorb calcium from food. However, a calcium deficiency is rarely seen in blood tests. This is because your body has a high demand for calcium for important functions such as muscle activity. To ensure it can always perform these, the body draws calcium from its largest store – the bones. As a result, the bone mineral content drops and bone density deteriorates. In the blood, the inactive precursor of vitamin D, 25-OH-vitamin D, can be tested. Since this test is relatively expensive, general practitioners are often reluctant to order it. Alternatively, the parathyroid hormone (PTH) level can be checked. This hormone is produced by the parathyroid gland and is released in greater amounts when the body is increasingly breaking down calcium from the bone. This shows whether the body is already tapping into its reserves and might need support in the form of calcium and vitamin D. Since the effects of celiac disease on the bones are so common and often pronounced without you even noticing, it is vital to carry out these examinations.
Another common deficit is a zinc deficiency. If symptoms such as an increased susceptibility to infections, poor wound healing, or problems with nails or hair are present, this deficiency should be investigated. In children and adolescents, a zinc deficiency can manifest as poor longitudinal growth. Therefore, zinc levels should always be checked in cases of short stature.
There are also other vitamins and minerals, such as vitamin K, which is important for blood clotting, or the electrolytes potassium or magnesium, which are sometimes not absorbed in sufficient quantities. Ultimately, there is practically nothing that does not occur in celiac disease. Depending on the symptoms, further blood tests may need to be added.
How should nutrient deficiencies be compensated for?
The normal source for all nutrients is, of course, our diet. To this end, it is necessary to know which foods contain which vitamins and minerals. A professional nutritionist can best teach you this. Such a consultation can also address what you enjoy eating and what you do not like at all. Furthermore, one must sometimes be aware that certain substances in foods can hinder each other's absorption. For example, phytates in legumes can reduce the absorption of zinc and iron, or oxalic acid in spinach and rhubarb can prevent the resorption of calcium. Conversely, however, consuming Vitamin C from a glass of orange juice at the same time increases the absorption of iron, especially from plant-based foods such as amaranth, quinoa, and millet. Therefore, it is not always enough to look up which foods contain which nutrients online; one must also be aware of potential interactions. This can then be taken into account to achieve the best possible supply.
When should dietary supplements be used?
Correcting deficiencies through diet takes time. This is because the inflammation must first subside enough for the mucous membrane to regenerate. Only then can proper nutrient absorption take place again. If the deficiencies are very pronounced or the symptoms are very distressing—which can be the case with anemia due to significant iron deficiency—one must consider whether additional medicinal supplementation is required.
Good to know!
Dietary supplements must generally be paid for out of pocket by those with statutory health insurance. There are only a few exceptions—such as iron supplements for diagnosed anemia—that are reimbursed by the health insurance provider.
Your doctor can now prescribe tablets for you, and the pharmacy can advise you on certain dietary supplements. However, with tablets or liquids, there is initially the problem that the still-inflamed and flattened mucous membrane cannot absorb the nutrients well. Especially with iron, this can lead to increased side effects, as many people do not tolerate these preparations well. Loss of appetite, nausea, constipation, and abdominal pain occur more frequently—all symptoms you may already be experiencing from your celiac disease.
Tip
Wait about 3 months before you start taking iron supplements. By then, your mucous membrane will have recovered a little and will be able to absorb the iron.
In the case of iron, infusion therapy can also be considered for severe anemia with corresponding symptoms. In the past, these iron infusions had serious side effects in the form of allergic reactions. Therefore, there is often still a great deal of reluctance to administer iron infusions. Today's preparations are much better tolerated and suitable for introducing iron into the body quickly and independently of the intestinal mucosa. This then alleviates the symptoms as quickly as possible.
For other deficiencies, it is actually usually sufficient to provide appropriate supplements. It should be ensured that they can be absorbed by the body as well as possible. This is called bioavailability. This depends on the chemical compound in which the mineral is offered to the body.
To make this easier to understand, let's take the example of zinc:
Zinc sulfate or zinc oxide are not as well absorbed and can cause gastrointestinal complaints, but they are usually significantly cheaper. Zinc acetate is absorbed better. And zinc gluconate, citrate, and picolinate are absorbed the best. In this way, you can choose a highly effective supplement or have one recommended by a doctor or pharmacist.
Practical Tip
As mentioned above, zinc absorption can be reduced by foods containing phytic acid, such as legumes, as well as coffee. Furthermore, if you consume dairy products, which are high in calcium, at the same time, the zinc will not be absorbed well either. Therefore, take zinc before breakfast and not with milk or coffee!
The best of both worlds – nutrition and tablets
You would likely prefer to take as few tablets as possible. Ultimately, the goal is to obtain nutrients as completely as possible through your diet. Therefore, it is definitely worthwhile to discuss with an experienced nutrition professional how you can achieve this through your diet. For example, you can meet your calcium requirements through your diet by consuming sufficient dairy products or calcium-fortified milk alternatives and calcium-rich mineral water. Vitamin D, on the other hand, is very difficult to obtain through diet alone, as hardly any food contains enough of it. Therefore, supplementation with tablets can ensure adequate levels here.
Tip
Vitamin D is a fat-soluble vitamin. Therefore, take it with a meal that also contains fat. This ensures that the vitamin D is actually absorbed.
The "watering can" approach – is more always better?
On the other hand, many affected individuals feel, especially at the beginning, that they should be taking some kind of pill or supplement rather than "just" buying a different type of bread. They often reach for an A–Z multivitamin supplement to replenish "everything." This is certainly understandable. However, I would like you to consider that the composition of a multivitamin tablet is highly unlikely to be exactly what YOU need to correct YOUR specific nutrient deficiencies. Furthermore, such a supplement may contain components that you cannot absorb well at all. If you take multiple supplements, it can also lead to overdosing. That is why I am not a big fan of simply popping one or even several tablets. And definitely not on a long-term basis, just because you think that taking a few vitamins "can't hurt." It is important for your doctor to examine where the deficits lie so that supplementation can be targeted. This should then be monitored and discontinued once your stores are replenished.
Since many doctors often struggle to order such extensive testing, you can refer them to the celiac disease guidelines. In them, experts have specified which tests are useful at the beginning and later in the course of the condition. You can use this as a guide – it represents high-quality care for everyone affected by celiac disease.
In a nutshell
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The most common nutritional deficiencies involve iron, folic acid, vitamin B12, calcium, and vitamin D, but zinc should also be considered.
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For newly diagnosed celiac patients, the celiac disease guideline recommends that these deficiencies be examined. You may refer to these.
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Documented deficiencies can be addressed through diet (with the support of a nutrition professional) or through medication or dietary supplements. In some cases, it may be necessary to correct a severe deficiency via infusion.
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Appropriate follow-up examinations should be performed to see that the stores are replenishing.
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Dr. Stephanie Baas
Ärztin und Zöliakie-Expertin