What Is Manganese Deficiency?

Overview

Manganese is a naturally occurring metal element. Manganese is vital to many biological processes in the body that keep you healthy. Manganese deficiency is incredibly rare but has been studied experimentally. This article discusses why manganese is important and what would happen if you were diagnosed with a manganese deficiency.

Introduction to manganese deficiency

Manganese is a metal element that occurs naturally in the environment. For humans, manganese is an essential mineral because it plays an important role in many biological processes. In human tissues, manganese is one of the most common metals found. Despite the body’s high demand for the mineral, manganese deficiency is very rare. The rarity of the deficiency is due to the extensive dietary sources.¹

What are the functions and roles of manganese in the human body?

Manganese is used by human tissues to carry out many different biological functions. Within your tissues, manganese binds to protein molecules to form what are known as manganese metalloproteins.² In metalloproteins, the metal ion provides additional biochemical properties that the components of proteins (amino acids) do not possess by themselves. Manganese helps proteins to fulfil their enzymatic role. Without enzymes, many of the biochemical reactions that keep us alive would not occur.³ Manganese or manganese metalloproteins play a role in:^{1, 4, 5, 6}

• Metabolism: Manganese metalloproteins help catalyse the metabolism of glucose, carbohydrates, amino acids and cholesterol.
• Bone Formation: Manganese metalloproteins are important enzymes in the production of new bone and cartilage.
• Free-Radical Defence: The manganese metalloprotein known as MnSOD detoxifies reactive oxygen species that otherwise could cause damage to your cells.  
• Reproduction: Reproductive hormones such as testosterone, oestrogen, and progesterone are a class of steroid hormones. Steroid hormone molecules are synthesised from cholesterol. Manganese metalloproteins are important catalysts in the synthesis of cholesterol.
• Blood: In combination with vitamin K, manganese metalloproteins catalyse the process of haemostasis, or stopping bleeding, and blood coagulation/clotting.
• Brain and Nervous System: Manganese metalloproteins are critical for the development of the brain and nervous system. Manganese also plays a role in maintaining optimum cognitive functioning.

What are the sources of manganese?

Manganese deficiencies are incredibly rare due to the abundance of dietary sources. Manganese is found in:¹

• Grains (wheat germ, oats, bran, rice)
• Sea Food (clams, oysters, mussels)
• Nuts (hazelnuts, almonds, pecans)
• Seeds (flax, sesame, pumpkin, sunflower, pine nuts)
• Legumes (soybeans)
• Leafy Vegetables (spinach)
• Coffee
• Tea
• Spices (black pepper, chilli powder, cloves, saffron)

Manganese is also present in water supplies and can be taken as a vitamin supplement. Once ingested, manganese is absorbed into the small intestine, where it is then transported in the bloodstream to organs that have a high demand for the metal, such as the liver, pancreas, pituitary gland, kidney and bones.⁷

What are the causes of manganese deficiency?

It is important to remember that manganese deficiency has never been reported in a healthy individual. There are also no known groups at risk of developing a deficiency of manganese.¹ Theoretically, a manganese deficiency could be caused by:

• Inadequate dietary intake
• Malabsorption and gastrointestinal disorders
• Medications and chemical interactions

What are the symptoms of manganese deficiency?

As manganese deficiency has never been diagnosed in the clinic, the symptoms listed are derived from a series of experimental settings and models. From the experimental data, the symptoms observed were:³

• Transient skin rash
• Altered metabolism of cholesterol and carbohydrates
• Abnormal glucose tolerance (manganese is being investigated in relation to type II diabetes)
• Impaired bone growth and skeletal abnormalities
• Decreased fertility
• Increased pain and altered mood associated with the premenstrual phase
• Lower cognitive function

The experimental models used to obtain these potential symptoms may not reflect the actual symptoms of a manganese deficiency in humans. However, these experiments are useful predictors and can provide further insight into the inner workings of the human body.

How is manganese deficiency diagnosed?

Manganese levels are not routinely tested. However, if after evaluating your symptoms and medical history, your healthcare provider wants to test for manganese, they will detect the levels in your blood, serum, or urine.¹ As manganese deficiency would be an exceptionally rare diagnosis, your healthcare provider may test for other nutritional deficiencies or conditions that cause a similar set of symptoms.

What is the treatment for manganese deficiency?

If you are diagnosed with low manganese levels, your healthcare provider can advise you on dietary changes to ensure you are eating manganese-rich foods. If your dietary intake is already adequate, you may also be given manganese supplements.¹

How can I prevent manganese deficiency?

As manganese is present in so many different foods, eating a healthy, balanced diet will mean that you take in a sufficient amount. If you are worried about getting enough of any specific vitamin or nutritional group you can get advice from a registered dietician.¹

Can I have too much manganese?

High levels of manganese are toxic. However, there has never been a case of manganese toxicity caused by a high dietary intake. The two predominant causes of manganese toxicity are:¹

1. Chronic inhalation of manganese dust through occupational exposure
2. Consumption of water with high manganese levels

Manganese toxicity is serious due to its effects on the central nervous system.¹ If you are worried about exposure to high levels of manganese, it is important you seek help from a healthcare professional.

Summary

A deficiency in manganese is a rare diagnosis. If you eat a balanced diet, you will have an adequate intake of manganese. Manganese deficiency is treatable by increasing dietary intake or through supplementation. It is difficult to consume too much manganese. However, exposure to high levels of manganese in the air (manganese dust) or water can lead to manganese toxicity. Although manganese deficiency is rare, it is not uncommon to be deficient in other vitamins or minerals; if you are worried about getting enough nutrients in your diet, you can get advice from a registered dietitian.