You might have read that an alkaline diet is going to be the saviour of your health, or even that specific Hollywood celebrities are advocates, including Jennifer Aniston, Gwyneth Paltrow, Kirsten Dunst, and Kate Hudson. Proponents of the diet like to think that this way of eating – also known as the “alkaline ash diet” or “alkaline acid diet” – can help you lose weight and dodge chronic health or life-limiting health problems like arthritis and cancer. This is because some foods – like meat, wheat, refined sugar, and processed foods – cause your body to produce acid, which is bad for health. It then follows that eating foods that help your body be more ‘alkaline’ will make you healthy.
The premise is this
The alkaline diet is based on the idea that replacing acid-forming foods with alkaline-forming foods can improve your health. When food is broken down in your body – rather like fire – an “ash” (metabolic waste products) is left behind and this ash can be acidic or alkaline, and the ash makes your body either acidic or alkaline, too.
Alkaline v acidic foods
There is a sliding scale of those foods that are highly, moderately or mildly either alkaline or acidic. While there are exceptions (like tropical fruits, which creep into the moderately acidic range), most fruit and veg falls into the alkaline-promoting food groups along with tofu, many nuts and seeds, and beans and lentils. Base 80% of your diet on these foods.
Dairy, eggs, meat, most grains, and processed foods, like canned foods and processed snacks and convenience foods, fall on the acid side, as does alcohol and caffeine. Base 20% of your diet on these foods.
This is not to be confused with the immediate acidity of a food. Oranges, for example, are acid due to their citric acid content. However, citric acid is completely metabolised and the net effect of eating an orange is to alkalise the body, hence it is classified as alkaline-forming.
In the simplest terms, pH is a measurement of how acidic or alkaline something is.
The pH value ranges from 0–14, with acidic values being 0.0–6.9, neutral being 7.0, and alkaline being 7.1–14.0.
In reality, your blood acidity/ alkalinity is very closely regulated by a series of checks and measures known as acid-base homeostasis. Although minor fluctuations occur, the pH of blood in healthy people stays pretty constant.
Food can change the pH value of your urine and getting rid of excess acids via your urine is one of the ways your body regulates the pH of your blood and it’s not necessarily a good indicator of your overall acidity or alkalinity.
The controversy is whether the acid/alkaline balance of your diet has any noticeable effect. Some say it’s all hocus-pocus, others propose an alkaline diet (as well as giving alkalising agents such as sodium bicarbonate) as a miracle cure for cancer.
Is too much acid bad for you?
An increasing amount of evidence supports the need to have an acid/alkaline balanced diet. Recently, a study in Japan of 92,000 people who had no diseases at the start of the study found that, 13 years later, when almost 13,000 had died, the higher the acid load, the greater was the risk of dying from heart disease. No association was found in relation to cancer risk.
Another Japanese study involving women aged 65-94 years found that the higher the acid load, the greater their fragility, which was defined as the prevalence of slowness/weakness and low physical activity.
A further Dutch study of people over 45 found that the higher the acid load, the lower their bone density was, as measured by the trabecular bone score. Researchers also found that a higher meat-based protein intake (but not a higher vegetable-based protein intake) increased risk to bone integrity.
This also seems to be borne out in research into kidney disease, where the greater use of vegetable proteins and increased fruit and vegetable reduced the risk and slowed progression or occasionally improved renal function for those with kidney disease.
Does an alkaline diet cure cancer?
Cancer cells produce a lot of acid secretions like lactic acid. Otto Warburg, contemporary of Einstein’s, proposed that cancer cells develop because, being starved of oxygen, they switch to anaerobic metabolism, which generates acids. So, the idea developed that if you could alkalise the environment of a cancer cell it might not be able to survive.
Overall there is a lack of evidence to suggest this is helpful or that an alkaline diet holds the key to curing cancer. However, there are encouraging animal studies showing that alkalising the environment of cancer cells does help suppress its growth. There have also been some small-scale studies on humans with tumours. The results look promising, but more work is needed – a larger clinical trial.
The bottom line
Is an alkaline diet healthy? In short, yes, but largely because it is based on your eating whole, unprocessed, real food rather than relying on processed foods and on eating more vegetable proteins, and fruit and veg in general. We should all aim to be doing more of that.