The recommended salt intake for most adults is 6 grams per day. However, the average consumption in the UK is 9 grams a day, 50% more than would be considered healthy. This overconsumption of salt is understandable considering how many foodstuffs contain the substance. Bread, biscuits, breakfast cereal and most other processed foods contain some salt. This can make it challenging to adopt a low sodium diet.
A new drug, called Tenapanor, could one day be used to reduce the amount of salt the body absorbs during digestion. The drug is currently in the early stages of clinical trials. It prevents a molecule found in the cells of a person’s intestines from transporting sodium into the body. The trials have shown that up to a third more sodium can be excreted directly (rather than absorbed into the body and filtered through the kidneys) whilst taking Tenapanor.
High salt diets have been linked to heart and kidney conditions as well as raising blood pressure. Tenapanor has been developed with kidney patients in mind, to help ease their job of filtering sodium from the body. The fact that it could reduce absorbed sodium levels by a third would surely bring significant benefits to people with kidney conditions, who are supposed to eat less than 5 grams of salt a day. According to Dominique Charmot (of Ardelyx, the Californian company responsible for creating the drug) Tenapanor could also be used to help people afflicted with other conditions that require a low salt diet.
Tenapanor has been compared to weight reduction drugs, like Orlistat. Marketed under the names Alli or Xenical, the medication inhibits the gut’s ability to absorb fat. As well as the perceived advantages of such a drug, there are also side effects to contend with. Orlistat can cause issues with digestion, including incontinence. According to Charmot, the side effects of Tenapanor are significantly easier to cope with.
It is believed that – because the drug stays exclusively within the digestive system, refraining from entering the bloodstream – it is extremely unlikely that Tenapanor will affect any other bodily functions. It is therefore expected that any other side effects would be unlikely. This is still an uncertain claim, though it should become clear once the results from larger trials have been collected.
Despite only being in the early stages of development, Tenapanor is already attracting positive comments from the scientific community. The leader of the campaign group Consensus Action on Salt & Health, Graham McGregor of the Wolfson Institute of Preventative Medicine in London, commented on the potential of the drug and said: “It’s an interesting concept”.
Charmot has great belief that Tenapanor will become a well-known drug in the future: “It’s a way to help people comply with very strict sodium [targets]. It’s rare people can achieve that.” Considering that our national average for salt consumption is so high, this seems like a fairly safe claim. Despite prolific recommendations for people to adopt lower salt diets, and avoid processed foods, we still consume too much sodium. Assuming that this doesn’t change, Tenapanor may eventually be used to treat millions of patients, and allow them to lead to longer, healthier lives.
How could this drug change the way we think about diet and its effects on health?