How to help clients overcome nutrient deficiencies

How to help clients overcome nutrient deficiencies

Consuming the proper amount of nutrients is essential to good health, yet many people are deficient in some essential nutrients (including iron, vitamin D, vitamin B12, calcium, and iodine). What causes these nutrient deficiencies, and how does this affect overall health? Here are some science-backed ways to help your clients.

Nutrient deficiencies can cause many unpleasant feelings that may negatively impact overall health. Many people are unaware that they are deficient in any nutrients, yet deal with symptoms every day. These symptoms vary depending on the deficiency but can include fatigue, diarrhea, lack of appetite, muscle weakness, and shortness of breath.

Before discussing nutritional care, let’s start off with some common nutrient deficiencies and what you should look for when evaluating your clients.

Common nutrient deficiencies

Having a nutrient deficiency can greatly impact your clients’ quality of life. While people can be deficient in many vitamins and minerals, here are five of the most common ones:


This is the most common micronutrient deficiency with >20% of women experiencing it through their reproductive period of life [1]. Iron deficiency is common due to blood loss due to menstrual cycles, as well as not consuming enough iron-rich foods. Some common symptoms of an iron deficiency include diminished exercise capacitygastrointestinal discomfortfatigue, and disturbed thermoregulation [2].


nutrient deficiencies: RDAs for Iron

Vitamin D

Having a deficiency in “the sunshine vitamin” is common due to our modern lifestyle of indoor work and activities. Vitamin D can be synthesized by our skin from exposure to UVB rays, however, few of us get enough sun to make adequate vitamin D. And, since vitamin D is only found in a few food sources, many of us fall short, which is why studies show that about 42% of people are deficient in it [3]. Some symptoms of a vitamin D deficiency include muscle weaknessbone loss, and an increased risk of fractures [4].

nutrient deficiencies: RDAs for Vitamin D


The concentration of calcium in our blood is closely regulated, so when there is excess calcium, it’s stored in our bones. If there is a deficiency, our bones must release some calcium to compensate, which can lead to weak (or brittle) nails, easy fracturing of bones, and lowered bone mass [7]. Studies show that fewer than 22% of men and 10% of women meet the recommended calcium intake [8].

nutrient deficiencies: RDAs for Calcium

Vitamin B12

Vitamin B12 is an essential nutrient for the body, but it can only be obtained from food or supplements because it is not naturally produced in the body. Since vitamin B12 is found in many animal products, 80-90% of vegetarians and vegans are deficient in this vitamin, making supplementation necessary [5]. Some common symptoms of a vitamin B12 deficiency are impaired brain functionlack of energyextreme tiredness, and raised homocysteine levels [6].

nutrient deficiencies: RDAs for Vitamin B12


This is one of the most common nutrient deficiencies, as one-third of the world is deficient in iodine [9]. Iodine maintains proper thyroid function and thyroid hormones, so a deficiency can cause many different symptoms, with the most common one being an enlarged thyroid (goiter). A high heart rateweight gain, developmental issues, and shortness of breath are all also common symptoms of iodine deficiency.

nutrient deficiencies: RDAs for Iodine

A well-balanced and nutritious diet can prevent many deficiencies as well as provide positive health benefits.

As a nutrition professional, it is important for you to evaluate your clients’ diets, record any negative symptoms, analyze biomarker results, and then provide appropriate nutritional care. Paying close attention to any symptoms correlated with deficiencies is crucial in order to determine if your client needs to make dietary changes.

How to help your client overcome nutrient deficiencies

To provide nutritional support, it’s important to do proper testing so you can determine how to best help your client. This can include running some bloodwork, physical exams, and any additional tests that you feel might be necessary. Once you have identified any nutritional deficiencies, you can then start planning proper nutritional care. Each deficiency will require different nutritional support, but here are some recommendations for how to properly assist your client in overcoming their nutrient deficiency.

Incorporate additional foods

Once you have identified nutrient deficiencies, you can add more of these nutrients into your clients’ diet via specific foods. Here are some common foods that are high in these respective nutrients:

Iron: red meat, leafy greens, beans, and whole grains (such as oats and quinoa) [10].

Vitamin D: fatty fish (such as salmon, herring, and sardines), egg yolks, and mushrooms [11].

Calcium: dairy products, **green vegetables (such as kale, spinach, and collard greens), and fortified foods [10].

Vitamin B12: meat, shellfish, eggs, and whole milk [10].

Iodine: dairy, eggs, and fish (such as cod, halibut, and tuna) [10].

Supplementation needs

In certain cases, only eating a diet rich in these nutrients may not be sufficient enough to raise the levels within your client’s body. When this is the case, you should begin looking into supplementation and how to effectively and safely implement them into your nutritional care plan. While each clients’ needs are different (and should be evaluated as such), here are some overall supplemental recommendations:


Depending on the level of deficiency, a multivitamin can be recommended (this would provide about 18mg of iron or 100% of the DV). If your client is extremely deficient in iron, it may be necessary to independently supplement iron, but it is recommended to monitor them carefully and closely as excess iron can be harmful [12]. An acute intake of more than 20 mg of iron from a supplement can cause gastrointestinal discomfortconstipationnauseavomiting, and faintness [13].

Vitamin D

Taking a vitamin D supplement is extremely common and can be beneficial for the average person if taking the correct amount. The dosing can range anywhere between 2 mcg to 100 mcg, depending on how deficient the individual is [14]. You can determine what supplement dose is best for your client based on their labs and exams. Another way to get vitamin D is from 15 minutes of daily sun exposure, but overall, supplementation and food is the safest way to increase vitamin D levels [11].


Advising your client to take a calcium supplement can be beneficial if taken correctly. Calcium supplements are best absorbed when taken with food, regardless of the form. Typically the supplement will contain about 200 to 500 mg of calcium because anything higher than that will decrease the percentage absorbed [15]. One thing to be aware of is that they can experience some gastrointestinal discomfort from calcium supplementation, so if this occurs, it is recommended that they try a new form, lower the dose, or take it with meals [16].

Vitamin B12

This is available in multivitamins, other B-complex vitamins, and B12 only supplements. The dosing can range from 5 mcg all the way to 1000 mcg depending on which vitamin complex you choose and what your client needs. Vitamin B12 is generally tolerated well because it has a low potential for toxicity and does not store excess amounts [17].


In supplements, it is usually presented as potassium iodide or sodium iodide and is usually at a dose of around 150 mcg. Studies show that iodine is absorbed almost immediately when taken as a supplement, so it is important to be aware of your client consuming excess iodine acutely [18]. The symptoms of excess iodine are similar to iodine deficiency, with acute symptoms like nausea, vomiting, and diarrhea. It is recommended that you check the ULs for iodine-based on age and gender for your client before considering supplementation.


Nutrient deficiencies can diminish your clients’ quality of life, and as their dietitian, you should monitor their nutrient levels closelyIron, vitamin D, vitamin B12, calcium, and iodine are some of the most common nutrients that people tend to be deficient in due to a lack of variety in their diet. Under the guidance of a dietitian, your client can increase their nutrient levels after having thorough testing and subsequently introducing a nutritious diet and appropriate supplementation.

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[10]- FoodData central. (n.d.).

[11]- U.S. Department of Health and Human Services. (2021). Vitamin D- Fact Sheet for Health Professionals. NIH Office of Dietary Supplements.

[12]- U.S. Department of Health and Human Services. (2021). Iron- Fact Sheet for Health Professionals. NIH Office of Dietary Supplements.

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[15]- U.S. Department of Health and Human Services. (2021). Calcium- Fact Sheet for Health Professionals. NIH Office of Dietary Supplements.

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[17]- U.S. Department of Health and Human Services. (2021). Vitamin B12- Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. [18]- U.S. Department of Health and Human Services. (2021). Iodine- Fact Sheet for Health Professionals. NIH Office of Dietary Supplements.