Combatting Common Nutritional Deficiencies

Despite a growing interest in nutrition, research shows that even in high-income countries inadequacies and deficiencies can be common for some nutrients. Some nutritional deficiencies cause distinct symptoms (e.g a long-term lack of vitamin B12 can cause tingling in hands and feet), however, for many the symptoms can be hard to recognise and are often masked by the physical and mental stressors of modern life, especially in the early or subclinical stages. These symptoms can include a lack of energy, poor sports performance and recovery, insomnia and pain.

Why Do Nutritional Deficiencies Develop?

There are a number of interacting factors that can contribute to the development of deficiencies, including:

Poor Dietary Quantity or Quality - Loss of appetite, or restrictive, unbalanced and low-nutrient diets.

Increased Requirements - During pregnancy and lactation, infancy, childhood and adolescence, nutritional needs for rapid growth and development are significantly increased.

Increased Metabolic Losses – Seen in critically ill patients with injury or infectious disease.

Impaired Digestion or Absorption - Gastrointestinal disorders, such as inflammatory bowel disease or coeliac disease.

Poor Nutrient Bioavailability/Bioconversion – low absorption/conversion of nutrients from plant-based diets (e.g zinc, iron, and vitamin A).

Common Nutritional Deficiencies


Iron is one of the most important components for the manufacture of healthy red blood cells. Research shows that nearly half of adolescent females and almost 1 in 4 adult women in the UK have been found to have low iron stores. Due to an increase in the destruction of red blood cells, iron needs are often greater in athletic populations, particularly runners, and therefore risk of iron deficiency is also increased. Furthermore, following a vegetarian/vegan diet is also a contributing risk factor, due to the avoidance of meat and the lower absorption and bioavailability of iron in plant-based foods.

Symptoms of low iron include excessive tiredness, low energy, impaired immune system, hair loss and disturbed sleep.

What to eat: Red meat and offal are the best sources of iron, this is  because they have a high iron content and also offer superior absorption and bioavailability.  Good plant-based sources of iron include dark leafy vegetables like kale, legumes (lentils, beans, pulses), tofu, cashew nuts, and fortified breakfast cereals.


The need for calcium is often linked to the development of strong bones and teeth, but it also plays an important role in the heart, nervous system, and muscle contraction.

Most people are not aware when they do not have enough calcium. This is because the body can reabsorb calcium from our bones when there is low availability from the diet. For this reason, often the very first symptom of calcium deficiency is an unexpected fracture. Other symptoms of calcium deficiency include insomnia, low blood pressure, anxiety, and cramping.

What to eat: Our calcium needs can be met by consuming 3 portions of dairy (yogurt, milk, cheese) a day, if you can't tolerate cow's milk choose a dairy free milk which is fortified with calcium and vitamin D. Non-dairy sources of calcium include spinach, canned fish like sardines which are eaten with their bones, tahini and pulses.

Vitamin D

Vitamin D is a fat-soluble vitamin, is essential for calcium absorption and bone health, and plays an important role in many physiological processes, including the immune system. Most of the vitamin D we need is synthesised in the skin from sunlight, which is dependent on skin exposure and inhibited by clothing and sun cream protection. Research suggests that 1 in 5 people aged 19-64 in the UK have low levels of vitamin D in their blood.

Poor vitamin D status negatively affects muscle function, increases risk of bone and gum problems, and can weaken the immune system.

What to eat: Diet alone is unlikely to provide sufficient vitamin D and the body can't make enough in the winter months. For this reason, it is recommended that vitamin D is supplemented during autumn and winter. Dietary sources include oily fish, egg yolks, and fortified foods.


Iodine is a mineral that is a key part of the thyroid hormones that are needed for many biological processes including growth, metabolism and for the development of a baby’s brain during pregnancy and early life. Research shows that iodine deficiencies appear to be less likely in childhood, however, there is evidence that teenage girls, young women and anyone who doesn't eat dairy has a greater risk of deficiency.

A long-term low intake of iodine will cause your thyroid to work harder to try to keep the right level of hormones in your blood. Symptoms of deficiency include tiredness, muscle weakness, breast pain, and sudden  unexplained weight gain.

What to eat: The richest sources of iodine are white fish, milk, and dairy products. It is important to be aware that most milk-alternative drinks (e.g. soya/almond/oat) are not fortified with iodine and have a low iodine content. Seaweed is a very concentrated source of iodine, but it can provide excessive amounts and therefore, the consumption of seaweed should be limited to just once a week, especially during pregnancy.


Omega-3 fatty acids are important for normal growth and development, play an important role in cardiovascular health, inflammatory and chronic disease, and immune function.  Both Omega-6 and Omega-3 fatty acids are essential, however, the long chain Omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are considered to be under-consumed in the modern western diet in general, and in vegans/vegetarians in particular; due to an absence of marine-sourced fats.

A low intake of omega-3 might have important health implications including an increase in the risk of heart and cognitive problems.

What to eat: The best source of Omega-3 is oily fish (sardines, fresh or canned salmon, mackerel) and it is recommended to consume at least two portions a week. ALA (α-linolenic acid) is the type of omega 3 found in plant sources (i.e flaxseed, chia, walnuts) and is valuable to health, however conversion to the essential types EPA and DHA is extremely poor at a ~8% and 0.5% efficiency, respectively. Therefore, supplementation of these might be required.

How can we help?

Dietary Analysis and Guidance

Our nutritionist uses research standard nutritional software to analyse the nutrient content of your existing diet, which includes a detailed report of the nutrient breakdown, and can provide feedback to ensure that your nutrient requirements are met.

Deficiency Screening

Our partnership with of one the UK’s top laboratories means we can offer literally 100’s of blood tests, which includes screening for important nutrients such as Vitamin D. Unlike many of the online services, we don’t want you wasting your money on unnecessary screening; our nutritionist and sports medicine doctor will be able to advise you on suitable tests based on your current health and symptoms, family history & nutritional goals.

Edward Gibson-Smith

Bupa Health Adviser / Sports & Exercises Nutritionist
Edward Gibson-Smith

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