Did you know that different foods and drinks effect the pH (relative acidity or alkalinity) of your body in different ways? If you did, then you may or may not have known this…
The effect that a food has on the pH of your body depends not on the pH of the food or drink, but rather the pH of the end products of these metabolised food or drinks. Milk for example, is an alkaline substance prior to consumption, however once it enters the human body the digestive and metabolic pathways that take place have some acid forming effects. In fact, dairy foods in general are known for their acid forming effects, although it’s worth noting that milks effects are relatively small. A 200ml glass of whole or semi-skimmed milk only causes an acid load of 1.4 milliequivalents (2/1000 of an equivalent). Compare this to eggs which have potential renal acid load (PRAL) milliequivalents of 8.2, and other non- dairy sources such as meat and meat products (average) which come in at 9.5 milliequivalents and you’ll note that milk in itself isn’t all that acid forming. Of course if you drink excessive amounts of the stuff, then problems with your acid/ alkaline balance may arise.
Enter cheese, this member of the dairy family poses a slightly higher potential to increase acidity. Like milk, cheese is relatively alkaline prior to consumption, but the by- products of cheese’ breakdown once eaten becomes quite acidic. In fact, Collison, D. (2010) states how parmesan cheese exerts the highest PRAL of all with a milliequivalent level of 34.2 (milk remember is 0.7 milliequivalents).
So it seems that many of the ‘healthy’, nutritionally dense foods we consume have some acid forming effects on our body. So should we be worried that meats, eggs, fish, grains and in particular cheese increases the pH of our bodies…no, not at all. You see, there’s this cliché term that everybody is so afraid to use because, well, its cliché… and that word is ‘balance’! A diet that delivers optimal, balanced ratios of meats, starchy carbs, dairy, eggs and fruit and veg, with sensible levels of tea and coffee is unlikely to send you into acidosis. The alkaline effects that fruit and veg have on the body are more than adequate to counteract the potential acidity caused by meat, dairy and cheese (if we don’t exceed daily recommendations such as 30g of cheese etc). Fruit and veg has the lowest PRAL and on average delivers a negative milliequivalent, spinach is one of the lowest coming in at -14 milliequivalents and baby carrots at -4.9. Far and beyond this is raisins which have a negative milliequivalent of -21.
So what does this mean for your body?
Should you not manage to achieve nutritional balance, and thus fail to maintain a pH harmony, then certain physiological processes may be effected. The pH in our body is designed to fluctuate, and the pH will drastically vary depending on what part of the body you measure. The highest acidity can be found in the stomach with a highly acidic environment of around 1.3-3.5. The skin is also quite acidic in order to defend against excessive microbial growth coming in at a pH of approx. 4-6.5. One of your body’s mechanisms for maintaining a consistent internal and external environment is urination, so urinal pH is variable based on the bodies need to equilibrate its acid/ alkaline balance. If the body was unable to manage its acidity then it could enter a state of metabolic acidosis. This may negatively impact the kidneys, increase the breakdown of muscle (atrophy), increase urinal output of calcium and thus increase the risk of chronic bone conditions such as osteoporosis and osteoarthritis. So it pays to get the balance right, a diet that is overly alkaline can cause as much damage to the body as an overly acidic diet. The key to maintaining homeostasis via optimal pH is to ensure your daily food and drink intake contains protein, carbs, fat and fibre in the recommended proportions described by the eatwell plate. Follow this and your body’s serum pH should hover around 7.35-7.45 which is optimal in order to survive.
Collison, D. (2010). PRAL - Potential Renal Acid Load. A Measure of the Effect of Foods on the pH of the Body* Retrieved 13th August, 2014, from http://www.huntlycentre.com.au/updates/posts/view/118
Schwalfenberg, G, K. (2012). The Alkaline Diet: Is There Evidence That an Alkaline pH Diet Benefits Health? Retrieved 13th August, 2014, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3195546/