Fun Facts
Life on Earth depends on appropriate pH levels in and around living organisms and cells.
Human life requires a tightly controlled pH level in the serum of about 7.4 (a slightly alkaline range of 7.35 to 7.45) to survive.
However, pH can vary throughout the body, depending on the need for acidity or alkalinity.
pH of selected fluids, organs, and membranes
Organ, fluid, or membrane | pH | Function of pH |
---|---|---|
(1) Skin | Natural pH is between 4 and 6.5 | Barrier protection from microbes |
(2) Urine | 4.6 to 8.0 | Limit overgrowth of microbes |
(3) Gastric | 1.35 to 3.5 | Break down protein |
(4) Bile | 7.6 to 8.8 | Neutralize stomach acid, aid in digestion |
(5) Pancreatic fluid | 8.8 | Neutralize stomach acid, aid in digestion |
(6) Vaginal fluid | <4.7 | Limit overgrowth of opportunistic microbes |
(7) Cerebrospinal fluid | 7.3 | Bathes the exterior of the brain |
(8) Intracellular fluid | 6.0–7.2 | Due to acid production in cells |
(9) Serum venous | 7.35 | Tightly regulated |
(10) Serum arterial | 7.4 | Tightly regulated |
Dietary Acid and Alkali
Human diets have significantly shifted since the hunter-gatherer era, especially after the agricultural revolution and industrialization.
Modern diets have reduced potassium, magnesium, and bicarbonate but increased sodium and chloride, contributing to metabolic acidosis, particularly as aging decreases renal acid-base regulation.
Low-carb, high-protein diets can increase kidney stone risk by altering urinary chemistry, such as decreasing urinary pH and magnesium and increasing calcium and uric acid levels.
Excess dietary protein with a high-acid renal load may decrease bone density if not buffered by the ingestion of supplements or alkali-rich foods.
However, adequate protein is necessary for the prevention of osteoporosis and sarcopenia; therefore, increasing the amount of fruit and vegetables may be necessary rather than reducing protein,
Excess sodium in the modern diet can lead to hyperchloremic metabolic acidosis, particularly in individuals consuming an acid-producing diet.
High sodium intake is also linked to increased risks of bone and muscle loss, hypertension, and osteoporosis, especially in aging populations. Potassium, often deficient in modern diets, can help mitigate some of these adverse effects.
Calcium from bone reserves, in the form of phosphates and carbonates, is released to maintain pH balance in response to the acidic modern diet.
This process can lead to significant calcium loss over time, potentially contributing to osteoporosis, although urinary calcium loss alone is not a direct indicator of the disease.
Adequate vitamin D levels above 32 ng/mL (80 nmol/L) may allow for appropriate intestinal absorption of calcium, magnesium, and phosphate when needed, balancing mineral and pH levels in the blood and supporting bone integrity.
A mild reduction of plasma bicarbonate results in a negative calcium balance, which could be improved by supplementing bicarbonate with potassium bicarbonate.
Alkaline diets result in a more alkaline urine pH and may result in reduced calcium in the urine,
Alkaline diets may result in a number of health benefits as outlined below.
- Increased fruits and vegetables in an alkaline diet would improve the potassium/sodium ratio, benefit bone health, reduce muscle wasting, and mitigate other chronic diseases such as hypertension and strokes.
- The increase in growth hormone with an alkaline diet may improve many outcomes from cardiovascular health to memory and cognition.
- An increase in intracellular magnesium, which is required for the function of many enzyme systems, is another added benefit of the alkaline diet.
- Available magnesium, required to activate vitamin D, would result in numerous benefits in the vitamin D apocrine/exocrine systems.
- Alkalinity may result in added benefits for some chemotherapeutic agents that require a higher pH.
- Consider an alkaline diet to reduce morbidity and mortality of chronic disease
Foods can be categorized by the potential renal acid loads (PRALs).
Fruits, vegetables, fruit juices, potatoes, alkali-rich, and low phosphorus beverages (red and white wine, mineral soda waters) have a negative acid load.
Grain products, meats, dairy products, fish, and alkali-poor and low-phosphorus beverages (e.g., pale beers, and cocoa) have relatively high acid loads.
Potential renal acid loads (PRALs) of selected foods
Food or food group |
PRAL mEq of: Cl + P04 + SO4 − Na − K − Ca − Mg |
---|---|
Dairy | |
Parmesan cheese | 34.2 |
Processed cheese plain | 28.7 |
Cheddar reduced fat | 26.4 |
Hard cheese (average) | 19.2 |
Fresh cheese (quark) | 11.3 |
Cottage cheese plain | 8.7 |
Yogurt whole milk | 1.5 |
Ice Cream | 0.8 |
Whole milk | 0.7 |
Buttermilk | 0.5 |
Eggs | |
Eggs yolk | 23.4 |
Eggs white | 1.1 |
Eggs chicken whole | 8.2 |
Meats | |
Corned beef | 13.2 |
Luncheon meat canned | 10.2 |
Turkey | 9.9 |
Veal | 9.0 |
Lean beef | 7.8 |
Frankfurters | 6.7 |
Sugars | |
Sugar white | −0.1 |
Honey | −0.3 |
Vegetables | |
Cucumber | −0.8 |
Broccoli | −1.2 |
Tomato | −3.1 |
Eggplant | −3.4 |
Celery | −5.2 |
Spinach | −14.0 |
Fats and Oils | |
Butter | 0.6 |
Margarine | −0.5 |
Olive oil | 0.0 |
Fruits and nuts and fruit juices | |
Peanuts | 8.3 |
Walnuts | 6.8 |
Grape juice unsweetened | −1.0 |
Orange juice unsweetened | −2.9 |
Apples or apple juice unsweetened | −2.2 |
Apricots | −4.8 |
Banana | −5.5 |
Black currents | −6.5 |
Raisins | −21.0 |
Grains and grain products | |
Brown Rice | 12.5 |
Rolled Oats | 10.7 |
Spaghetti whole meal | 7.3 |
Spaghetti white | 6.5 |
Cornflakes | 6.0 |
Rice white | 4.6 |
Bread rye flower | 4.1 |
Bread whole wheat | 1.8 |
Legumes | |
Lentils green and brown | 3.5 |
Green beans | −3.1 |
Fish | |
Trout brown | 10.8 |
Cod fillets | 7.1 |
Beverages | |
Beer pale | 0.9 |
Coca-Cola | 0.4 |
Beer draft | −0.2 |
Wine white | −1.2 |
Coffee infusion | −1.4 |
Wine red | −2.4 |
Want to Learn More?
Alkalizing the Urine for Better Health
Testing for Metabolic Acidosis
Reference
Schwalfenberg, Gerry K. “The alkaline diet: is there evidence that an alkaline pH diet benefits health?.” Journal of environmental and public health vol. 2012 (2012): 727630. doi:10.1155/2012/727630 This is an open access article distributed under the Creative Commons Attribution License,