The myth of ‘alkalising your body’

There are many myths about nutrition and health that swirl around the Internet, and regularly pop up in popular books and the mass media. One of the most pervasive is the notion that we should be striving to ‘alkalise our bodies’ in order to achieve optimal health and prevent cancer. Excess acidity, we’re told, is the root cause of every disease you care to name, from zits to cancer, and we must micromanage our intake of alkaline-forming and acid-forming foods, and even take alkalising substances such as sodium bicarbonate, to make our bodies more alkaline.

This topic was raised by an EmpowerEd member in one of our monthly ‘Ask Robyn’ sessions, and after it came up in a couple of consultations with my naturopathic clients this week, I thought it might be helpful for all my subscribers to learn the truth about our acid-alkaline balance.

(Side note for those who’ve forgotten their high school chemistry: acidity and alkalinity are measured using the pH scale, which runs from 0-14. 0 is highly acidic, 7 is neutral and 14 is highly alkaline [also called ‘basic’]. The pH scale is logarithmic, which means, for example, a pH of 3 is 10 times more acidic than a pH of 4, and a pH of 8 is ten times more alkaline/basic than a pH of 7.)

Like most of these myths, this one is promulgated by people who clearly have no understanding of human physiology. The question I always ask clients who have been taken in by this myth is, “Which body compartment do you think you should alkalise?”

Surely not your stomach, which operates correctly at an acidic pH of around 2, rising to 4-5 after a meal; if the stomach becomes less acidic, we absorb less iron from our food.

Not your intestines either. The acidity of the small and large intestines (except for the last part of the small intestine, which has a mildly alkaline pH of 7.4) is carefully maintained by various digestive secretions and also by beneficial gut microbes which produce lactic acid, short chain fatty acids and other acidifying chemicals from the foods we eat, in order to maintain an acidic environment which prevents the overgrowth of pathogenic organisms. Ditto the vagina, which is maintained at an acidic pH of around 4.5 by lactic acid-secreting bacteria.

Here’s just one example of the importance of maintaining an acidic pH in these compartments of the body: Candida albicans, the fungus that causes thrush, switches to a more virulent (disease-causing) form at a neutral-to-alkaline pH. Yes, you read that right: A more alkaline environment makes thrush worse. Still think alkalising your body is a good idea?

Most of the people who come to me with a cancer diagnosis have read or heard in some place or other that ‘cancer can’t thrive in an alkaline environment’. Oh, really? Then explain leukaemia and lymphomas, cancers of the blood and lymph (which is filtered from blood). Blood has a slightly alkaline pH of 7.4, and maintaining this pH is so important to our survival that if the pH drops below 7.35 or rises above 7.45, numerous buffering mechanisms (including blood proteins, phosphate, bicarbonate and the lungs and kidneys) kick into gear, in order to nudge blood pH back to 7.4.

Anything that overwhelmed those buffering mechanisms and made the blood either too acidic (below 7) or too alkaline (above 7.7) would quickly result in death, because the chemical reactions that keep you alive can only occur in a narrow pH range.

The take-home message is that each compartment of the body has a pH range that is necessary for its proper function, and which is carefully maintained by a range of powerful mechanisms. You simply can’t ‘alkalise your body’, nor should you strive to.

However, the one little raindrop of truth in the murky waters of the popular discourse on acid-alkaline balance, is that you can make it easier for your body to maintain its optimal pH ranges through making healthy food and lifestyle choices.

For example, by eating a wholefood plant-based rich in fibre and resistant starch from vegetables, fruits, legumes and wholegrains, you’ll be providing your gut microbiome with the carbohydrates needed to produce the short chain fatty acids that help maintain optimal pH in the colon.

To help maintain optimal pH in the vagina (and therefore stave off thrush) you can avoid using oral contraceptive pills and certain types of IUDs. (While you’re at it, check out my post on how hormonal contraception raises the risk of depression.)

And to help maintain optimal bloodstream pH, you can choose a diet rich in base-forming foods such as vegetables (especially green leafies) and fruits, and limit or eliminate highly acid-forming foods such as cheese, meat, chicken and fish.

But don’t forget, you’re not ‘alkalising your blood’ by doing this. You’re simply taking the load off all those buffering mechanisms which would have to work harder to maintain optimal pH if your diet predominated in acid-forming foods. And this does have considerable health benefits, including a reduced risk of kidney disease.

So go ahead and stack your plate or bowl with health-promoting fruits and vegies – they’re beneficial for just about every element of physical and mental health –  but for heaven’s sake, drop the silly notion of ‘alkalising your body’. Your body knows better than you, what its pH should be.

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