Nutrition and parasitic infections

People living in areas affected by parasitic worm infections including schistosomiasis (SCH) and soil-transmitted helminthiasis (STH), are commonly treated through mass drug administration programmes targeted at school-aged children. As treatment does not prevent reinfection, sustained access to adequate water supply and sanitation services – as well as avoidance of risk behaviours such as contact with contaminated water and poor food safety – are required.

The link between nutrition and parasitic infections 

A person infected will present abdominal pain, appetite loss and diarrhoea. As a result, parasitic infections affect a person’s ability to absorb nutrients and therefore have an impact on their nutritional status. The most common consequences are O, a blood disorder in which the blood has a reduced ability to carry oxygen, and stunting (short height for age). 

How do parasites cause anaemia? 

Anaemia in SCH-infected individuals is frequently ‘anaemia of inflammation’, leading to iron deficiency. Blood loss can also be caused by intestinal lesions, while urogenital schistosomiasis can decrease haemoglobin (a protein in red blood cells that carries oxygen) levels by increasing blood loss and decreasing food intake.  

STH feed on host tissues, including blood, causing loss of iron and protein; hookworms can cause chronic intestinal blood loss.  

The effect on anaemia, aerobic capacity, fatigue, weakness and reduced cognitive function and educational loss can result in lost productivity and capacity for work, contributing to a vicious cycle of disease, poverty, and undernutrition. 

How do parasites cause stunting? 

STH infection, particularly with roundworm and whipworm, has been associated with impaired growth in children under five years of age, linked with overall poor nutritional status. Roundworm may possibly compete for vitamin A in the intestine. SCH infection can result in slow growth due to continued or chronic inflammation during childhood.  

Integration of treatment against parasitic infections into health and nutrition programmes  

Treatment of school-aged children with anthelminthic drugs is effective in reducing infections; however, delivery of treatment solely through dedicated campaigns misses important opportunities for joint implementation with nutrition programmes that can lead to improved efficiency, reach and outcomes.  

Areas for potential integration that offer benefits for health and nutritional outcomes include community-based feeding, micronutrient supplementation and health promotion programmes.  

Such an integrated approach offers several important potential benefits, including allowing growth ‘catch up’ in early life to prevent the permanent effects of stunting; generating programme implementation efficiencies by delivering interventions through single mechanisms and/or joining distribution chains; and increasing the effectiveness of iron supplements or fortification by reducing disease and inflammation.    

Linking primary infection prevention efforts to prevention of undernutrition  

Environmental and behavioural measures such as improvement in access to safe water supply and sanitation services and hygiene practices are needed to prevent parasitic infections. This in turn can support prevention of undernutrition through reducing infectious diseases, diarrhoea and dysentery, and environmental enteric dysfunction (a subclinical state of intestinal inflammation). Collaboration between nutrition, disease control, and water and sanitation programmes, can therefore help ensure that services are delivered to communities with the highest burden of disease and undernutrition, while also contributing to programme efficiency and improved health outcomes. This includes use of data on the distribution of disease and undernutrition to improve the targeting and quality of water supply and sanitation services, and health promotion.    

What Unlimit Health is doing about parasitic worms and nutrition  

Unlimit Health is working to: 

• Improve evidence on the link between parasitic infections and nutrition through research collaboration 
• Develop programme and funding integration approaches particularly on paediatric treatment 
• Contribute to UK nutrition policy and advocacy through in the International Coalition for Advocacy on Nutrition (ICAN). 

If you’d like to know more about what we’re doing in this area, please contact Yael Velleman at y.velleman@unlimithealth.org