This is the first in a series of articles discussing various diet trends that have become popular in recent years, and whether the science supports their claims.
The alkaline diet has gained popularity in recent years, most likely due to a combination of celebrity advocates, scientific language, and an increasing interest in healthy living. But is it all it’s cracked out to be?
The alkaline diet is based on the premise that the body functions best in a slightly alkaline state, and that illness is due to acidity in the body. Some advocates even go so far as to claim that disease cannot live in an alkaline environment, and therefore if you have a disease (yes, that includes cancer!) it’s because your body is acidic. Sound a little far-fetched? Well that’s because it is, and here’s why.
Before we get into the nitty-gritty of these claims, we need to clarify some basic high school science. In chemistry, pH measures how acidic or how alkaline/basic a substance is. pH stands for “particles/power of hydrogen”, and measures the concentration of hydrogen (H+) ions. An acid has a low pH (low concentration of hydrogen ions) and an alkaline/base has a high pH. To put this into perspective, water is neutral and has a pH of 7, fizzy soft drinks have a pH of around 3 (very acidic), and baking soda has a pH of around 9 (slightly alkaline). For the sake of argument, alkaline and basic mean pretty much the same thing, but calling it the “basic diet” obviously doesn’t have the same ring to it!
Proponents of the alkaline diet say that what we eat and drink affects the pH of our bodies, including the blood. As the body is in a naturally alkaline state – the pH of your blood is 7.4 – they say we need to eat an abundance of alkaline-forming foods (namely fruits and vegetables), and avoid acid-forming foods (mainly meat and dairy).
The problem with this is that various parts of your body have a different pH. The stomach is highly acidic with a pH of around 2, the pH of your mouth is around 6 (the optimum pH for the enzyme amylase which kicks off the digestion process), and, as I said earlier, your blood has a pH of 7.4 (slightly alkaline). All foods that leave your stomach are acidic, and then enter the intestines where the stomach acids are neutralised by the pancreas. So even if you drink a litre of fizzy drink the end result in the intestines is alkaline. On top of that your blood pH never changes, as it’s highly regulated by a sophisticated buffer system. If your blood pH really was acidic, you would be dead, not merely unwell. Certain foods can leave end-products called ash that can make your urine acidic or alkaline, as it is the only part of your body affected by food. But the urine in your bladder is technically external, and therefore urine has no relation to body pH whatsoever.
Ok, you may argue, but your body neutralises any acid-ash using nutrients from your body, particularly phosphate ions which come from your bones, so if you overwork the phosphorous buffer system surely it has negative health effects? Well…yes, if you eat no vegetables and live off junk food for years, but surely that goes without saying? On top of that, several recent meta-analyses have found no link between acid-ash from dietary sources and osteoporosis. So the alkaline diet doesn’t even help prevent osteoporosis, and it creates restrictions on your diet which can actually create health issues if you’re not prepared.
Finally, I want to debunk this ridiculous saying that advocates fall back on, namely that cancer cannot grow in an acidic environment, and therefore if your body is alkaline you cannot get cancer. While cancer tissue does grow in an acidic environment, it’s the cancer that creates the environment, not the environment that creates the cancer. So eating alkaline won’t help – sorry! On top of that, anything that discourages individuals from life-saving conventional medicine should never be encouraged, ever.
But despite the glaring scientific flaws and ridiculous claims made by the alkaline diet, it has one advantage: it encourages people to eat more fruits and vegetables, which is never a bad thing. But it’s a shame that it relies on pseudoscience to get there.
Rather than worrying about acid and alkaline foods as their own “food groups”, if you simply eat a decent amount of fruits and vegetables (5 a day springs to mind), you have nothing to worry about. Quite frankly, anyone who says you can change the pH of your blood needs to be immediately directed to a high school chemistry classroom.