Can Papaya Seeds Be Used In The Treatment Of Intestine Parasites?

Different types of parasites can infect humans, many of which live in the intestines and cause harm, especially in children. For centuries, the seeds of papaya, a tropical fruit, were used in the treatment of parasites by locals in many parts of the world; this effect is now supported by scientific research.

In this article, you will learn about a group of intestinal parasitic worms called soil-transmitted helminths and how they are spread, diagnosed, and treated, and you will also learn about the role of papaya seeds in the treatment of these parasites. 

Intestinal parasites

Many parasites can target the human intestine and cause disease - these parasites can either be:

• Protozoa: single-cell microorganisms that can multiply in the human body (e.g. Giardia duodenalis), or 
• Helminths: parasitic worms that have many cells (multicellular) and cannot multiply in the human body (e.g. Enterobius vermicularis (pinworm))

Intestinal helminths are spread worldwide, and although they rarely lead to death, they can cause chronic infections that can damage the mental and physical growth of children¹. 

Soil-transmitted helminths (STH)

Soil-transmitted helminths are intestinal worms that can be transmitted through soil contaminated with their eggs. They spread in tropical and subtropical developing countries where sanitation and hygiene are poor and access to clean water is limited. 

An estimated 1.5 billion people are living with these infections. Although these diseases can be treated and prevented, they still cause suffering in the areas where they spread and are considered neglected tropical diseases (NTDs).

What parasitic worms are considered soil-transmitted helminths?

Three different types of worms are considered STH:

Ascaris lumbricoides

Also known as “ascaris”, large parasitic worms can reach up to 30 cm in length. These worms live in the small intestine of infected people, where they lay their eggs, which are passed in the stool. An estimated 807 million -1.2 billion people worldwide are infected with these worms.

Most infected people are asymptomatic, but in some cases, these signs and symptoms can appear:

• Abdominal pain 
• Cough
• Impaired growth in children 

Trichuris trichiura

Also known as “whipworms”, are small parasitic worms that can reach up to 45 millimetres in length. These worms live in the large intestine of infected people where they lay their eggs and pass them in the stool. An estimated 604-795 million people worldwide are infected with these worms. 

Most infected people have light infection (small number of worms) with no symptoms, but heavy infections (with many worms) can cause: 

• Painful bowel movements with mucus and blood in stools
• Rectal prolapse (a condition where the rectum, the last part of the large intestine, drops out of the anus)
• Slow growth and anaemia in children 

Ancylostoma duodenale, and necator americanus

Also known as “hookworms”, are small parasitic worms that can reach 15 millimetres in length. They live in the small intestine of infected people and pass their eggs with the stool. An estimated 576-740 million people are infected worldwide. Most infections are asymptomatic, but anaemia can occur in some cases. 

How are these parasitic infections transmitted?

These worms live in the human intestine and pass their eggs in the stool. In places with poor sanitation, infected people might defecate outdoors, which contaminates the soil with the worms’ eggs. 

In the case of Ascaris and whipworms, you can get infected when you touch your mouth with fingers that touch contaminated soil or when you eat contaminated fruits or vegetables without proper washing or cooking. The eggs then hatch and become adult worms in the intestine. 

In the case of hookworms, the eggs that are passed with the stool to the soil hatch and a larva (too small to be seen with the naked eye) comes out. When you walk barefoot in soil contaminated with these larvae, they can penetrate your skin and move to the intestine, where they become adult worms.

How are these parasitic infections diagnosed?

The healthcare provider will ask you for a stool sample.  Using a microscope, the healthcare provider will search the stool sample to try and find the worms’ eggs before making a diagnosis.   

How are these parasitic infections prevented?

These parasitic infections are preventable:

• Wash your hands with warm water and soap before handling food (click here for more information on proper hand-washing practices recommended by CDC)
• Teach children the importance of washing their hands regularly  
• Avoid touching soil that could be contaminated with human stools, for example, when stool is used as a fertiliser.
• All fruits and vegetables must be thoroughly washed, peeled, or cooked before they are eaten 

How are these parasitic infections treated? 

Many drugs, called anthelmintic drugs, are available and effective against these parasites. The drugs of choice to treat these parasites are albendazole and mebendazole. These drugs prevent the worm from taking in glucose (sugar) as a source of energy and lead to the immobilisation and death of the worms.^2,3

   These drugs can cause adverse effects; the most common with albendazole are:²

• Headaches 
• Elevation in the liver enzymes
• Abdominal pain
• Nausea and vomiting 
• Fever

and with mebendazole are:³

• Loss of appetite
• Nausea and Vomiting
• Headache
• Abdominal pain
• Diarrhoea
• Tinnitus (ringing in the ears)
• Flatulence (passing wind)
• Elevation in liver enzymes

Both drugs are highly effective against Ascaris, but albendazole is better against hookworms, and both drugs have low efficacy against whipworms. Also, the resistance against the anthelmintic drugs used in animals is well known, where drugs that used to be effective in killing the worms are not as effective anymore. Although not yet proven in humans, many scientists believe that it is a matter of time before resistance occurs.⁴ Therefore, the search for alternative treatment is needed.  

Papaya seeds

Carica papaya (also known as pawpaw) is a fruit that is found in tropical and subtropical regions and is known for its nutritional and medicinal uses. Papaya is rich in vitamins (A, B & C) and has antiviral, antifungal, and antibacterial effects. An enzyme called papain that is extracted from the plant is used in medications to relieve inflammation and pain, treat wounds and oedemas (swelling of tissues), and was found to have anticancer activity.^5,6

Papaya seeds form 25% of its mass, are round, dark in colour, and embedded in the fruit. The seeds are rich in oils and proteins and were used along with other fruits (e.g. fig and pineapple) for centuries by locals in South America and by doctors in Europe to treat intestinal parasitic infections.⁶

Is there scientific evidence to support the use of papaya seeds in parasitic diseases?

Many studies that have been carried out on lab animals and in humans support the anthelmintic activity of papaya seeds.

In mice, papaya seeds proved to be effective against intestinal parasites when compared to conventional drugs. Although the effects on mice treated with the drug started from the first day of treatment compared to papaya seeds that started working on day three, papaya was able to significantly reduce the worms’ burden (number of worms) and number of eggs in mice stools.⁷ Another study showed that papaya seeds were able to reduce the number of worms in rats.⁸

Many studies in poultry showed that introducing papaya seeds into chicken’s daily meals lowered the number of worms found in the chicken intestines or the number of worms’ eggs in the chicken’s stools.⁹

In humans, one study was done on two groups of school children infected with intestinal parasites, where one group was given air-dried C. papaya seeds elixir (sweet liquid) with honey and the other received only honey, showed that the group that received the papaya cleared intestinal parasites with no side effects.¹⁰

Another study was conducted on school children where papaya’s grounded seeds were added to school meals, and one group of the children included in the study consumed 300 mL of the porridge containing the seeds daily. The results showed that the children who received the papaya-containing meal experienced a reduction of eggs per gram of stools, which reflects that the burden of the infection (number of worms in the intestine) was decreased.¹¹

What is responsible for the antiparasitic activity in papaya seeds?

There are several compounds in the papaya seeds that are believed to be responsible for its parasite-killing effects. One compound is called benzyl isothiocyanate (BITC), which is formed when an enzyme called “myrosinase” acts on a compound called “benzyl glucosinolate”; these two are found in different parts of the seed; therefore, the seed must be crushed so these two comes together to create the BITC.¹² This compound damages the parasite's DNA and proteins.¹³ 

Other compounds are proteinase enzymes (enzymes that destroy proteins), which are believed to have evolved in the plant to protect it from insects and plant parasites. The proteinases that have anthelmintic activity in papaya are named papain and chymopapain; these enzymes can ingest and remove the parasite’s cuticle (an outer protective layer), causing the worms to lose their capability to move.^14,15

Summary

Many parasites can infect the human intestine and cause diseases that are especially harmful to school-age children. Soil-transmitted helminths are intestinal parasitic worms that are transmitted through soil contaminated with worms’ eggs, and they burden tropical and subtropical developing countries where sanitation is poor. Although effective drugs are available for treatment, there is a concern of emerging resistance against them that prompts the search for alternatives. Papaya seeds might be a suitable choice as they were used by locals and doctors to get rid of many intestinal parasites before these drugs were developed. Although many studies in animals and humans showed promising results that support their anthelmintic activity, more research is needed to determine the safe and effective dosage.