Acid byproduct during digestion induces drug resistance, worsens cancer as one ages

For a long time, many have been wondering why cancer seems to worsen as one ages. New research may have uncovered the reason behind this, and it has something to do with the acid that is produced during digestion.

In a study published Wednesday in the journal Nature, researchers from Weill Cornell Medicine in New York revealed that an acid called methylmalonic acid (MMA), which is a by-product of fat and protein during digestion, is shown to induce drug resistance in cancer cells, as well as aggressive metastasis. The researchers ascertained this after observing the cell behaviour in test tubes and also in mice.

Researchers noted that the metabolism of fat and proteins produces the MMA molecule, which accumulates in the blood of older people and endows cancer cells with an ability to further spread into different areas of the body. Normally, it is produced in very small amounts. However, there are diseases, wherein the body is not able to efficiently metabolise MMA. When this happens, it accumulates in the blood and becomes toxic.

The MMA levels in the blood of healthy older people over 60 were significantly higher as compared to those who are under 30. The researchers revealed that although there was an elevated MMA level, it did not cause the individuals to become ill.

What the researchers discovered, on the other hand, was that if cancer cells are treated with a serum, obtained from the blood of older individuals, which contains high levels of MMA, these cells adopt characteristics that are akin to that of metastatic cancer cells. This means the cancer cells could spread from the main tumour to seed cancer in other parts of the body. They then injected this into mice and the latter developed metastatic tumours in their lungs.

An explanation of the researchers as to why MMA levels in the blood increase with age showed that as one ages, the levels of vitamin B12 decreases. They noted that vitamin B12 deficiency was linked to MMA accumulation in the blood. The researchers said that this may not be the only reason for MMA accumulation.

The study noted that protein may be another reason, after ascertaining that a low-protein diet may reduce the substrates needed for the formation of MMA, as well as can enhance the anti-cancer immune response of the body.

Elderly cancer patient

The researchers also revealed that those individuals whom they studied with already high MMA levels were cancer-free. This underscores that MMA acts on cancer already existing in the body, rather than new formation of cancer.