Understanding the Impact of Diet on Blood pH
Even a moment spent pondering the amazing order and intelligence of the human body leaves one in wonder—trillions of cells conducting thousands of trillions of biochemical reactions each second with all the cells working together to form a most sophisticated creature. Even today science is only beginning to unravel the intricate details of our biological, chemical, and energetic functioning. However, one thing is clear, and that is the importance of homeostatic self-regulation and the maintenance of balance within the many systems in the body.
In this article we will discuss the most tightly regulated balance within the human body: pH balance. The pH of the blood must be maintained within a very narrow range or death quickly ensues, and deviations in cellular pH or in interstitial fluid pH (that is, the pH in the body fluid between blood vessels and cells) will generate a cascade of undesirable biological effects.
It is easy to understand the concept of pH balance when looking at bone health. For decades, scientists have documented the role bone plays in maintaining pH balance. When the blood is threatened with even a slight acidic tilt, bone alkaline mineral reserves are called upon to re-establish obligatory blood pH balance. (1)
Knowing that bone sacrifices itself to maintain blood pH balance provokes further questioning: “What other changes occur in biologic functioning when the blood pH takes on even a slight acidic tilt?” or “What causes increased blood acidity?” or “Can blood pH be altered by diet?”
The intent of this article is to advance general understanding of pH balance and, most particularly, clarify the impact that diet has on blood pH.
Deconstructing the misunderstandings around blood pH and diet
1. Researchers agree that for human survival blood pH must be maintained within a very narrow range.
The pH range of healthy oxygenated arterial blood is 7.35 to 7.45, and that of the carbon-dioxide-laden venous blood is 7.31 to 7.41.
Even slight changes in blood pH threaten life. To remain alive, the body must maintain a slightly alkaline blood pH—the viable human arterial blood pH range is just 7.4 plus or minus just 0.5 pH units. (1)
2. Researchers also agree that the body does an excellent job of maintaining blood pH within a narrow range.
Daily we produce a great deal of acid, some 70,000 mmol, but nearly all of it is buffered or excreted from the body spontaneously to maintain a life-supporting pH balance. (1)
There exist many intricate systems to both buffer and excrete excess acid:
- The three major buffer systems of our body are the carbonic acid bicarbonate buffer system, the phosphate buffer system, and the protein buffer system.
- The body eliminates non-volatile acids through the kidneys.
3. Many do not understand, however, that the foods we eat can impact and alter blood pH.
Scientists who measure blood pH by blood gases, hydrogen concentration, bicarbonate levels, etc., have long documented that higher intake of acid-forming foods increases blood acidity, albeit ever so slightly. Science also recognizes that even a tiny change in blood pH is important, as it translates into significant alterations in cellular functioning. Although buried deep in the scientific literature, these facts are still valid. In the words of nephrologist Dr. Lynda Frassetto, “Although the degree of diet-dependent metabolic acidosis is mild as judged by the degree of perturbation of blood acid-base equilibrium, it cannot be considered mild as judged by its negative biological effect.” (2)
It is perhaps because blood pH stays within the viable (“normal”) range that this diet-induced increase in blood acidity is overlooked in the popular literature.
To document the fact that diet can indeed alter blood pH, we only need look to contemporary pH science. Below, two of the most noted pH research scientists, Drs. Lynda Frassetto and Anthony Sebastian, explain the impact of diet on blood pH:
“In healthy subjects, higher dietary acid loads do lead to higher steady state blood acid levels, within the range considered to be normal. Both Kurtz et al. (3) and Frassetto et al. (4) using steady state diet data from healthy humans admitted to a metabolic balance ward, eating diets whose net acid loads were within the range typically observed in American and European diets, showed blood hydrogen ion concentration was significantly higher and the plasma bicarbonate concentration significantly lower. The body’s homeostatic mechanisms were unable to maintain previous hydrogen ion or bicarbonate levels with diet acid loads greater than ~1 mmol/kg/day.” (5)
This condition when the blood pH is balanced at the values close to the lower limit (7.35) is called low-grade metabolic acidosis. As researchers note, diet is one of the main factors that influence the occurrence of this condition. (6)This brings us back to the question: Why are even slight diet-induced changes in blood pH important?
4. Even a slight acidic tilt in the blood brings about dramatic changes in cell chemistry, biology, and activity.
When the blood pH takes on even a slight acidic tilt, the cells become more acid. The healthy range for intercellular cytoplasmic pH is 7.4 ± 0.1 and even the slightest tilt towards acidity dramatically impacts cell activity. (7)
As we documented earlier (1) and as many others have noted, a cellular acidic tilt is biologically costly and results in a variety of undesirable health outcomes including:
- Increase in bone breakdown and reduction of bone formation. (6,7,8)
- Nitrogen wasting and muscle loss. (2)
- Kidney stone formation. (6,9,10,)
- Swelling and impaired mitochondrial and transport with reduced ATP production, resulting in fatigue. (11)
- Less efficient protein synthesis. (6)
- Increased membrane free-radical production.
- Increased interstitial fluid retention. (11)
- Increased cortisol levels. (6)
- Suppression of growth hormone and other pituitary hormones.
- Predisposition to a series of degenerative diseases including diabetes, metabolic syndrome, osteoporosis, hypertension, and cardiovascular issues. (6)
5. It is important to fully understand the relationship between diet and blood pH.
We stand today poised for a worldwide awakening to the life-supporting nature of the Alkalizing Mineral Diet. Dozens of new studies from around the world document that higher intake of alkaline-forming foods reduces degenerative disease and enhances health in myriad ways.
These studies, done mostly in countries outside the US, explicitly contrast the “alkaline diet” with the “Western diet.” For those of us who have promoted the Alkaline Diet for decades, it is exhilarating to see the worldwide recognition of this life-supporting eating pattern. As these many studies document, the Alkaline Diet has the potential to substantially enhance health worldwide and to reduce the costly and painful incidence of degenerative diseases. The more we truly understand the scientific basis, i.e., the actual biology and biochemistry of the Alkaline Diet approach, the more successful our outcomes will be. Grounding ourselves in the science of pH balance builds a sturdy foundation for the regenerative Alkaline Diet movement.
- Brown, S. E., and R. Jaffe. 2000. Acid-alkaline balance and its effect on bone health. International Journal of Integrative Medicine 2(6).
- Frassetto, L., et al. 1997. Potassium bicarbonate reduces urinary nitrogen excretion in postmenopausal women. The Journal of Clinical Endocrinology & Metabolism 82(1):254-259. Doi: 10.1210/jcem.82.1.3663.
- Kurtz, I., et al. 1983. Effect of diet on plasma acid-base composition in normal humans. Kidney International 24:670–680.
- Frassetto, L., et al. 1996. Effect of age on blood acid-base composition in adult humans: Role of age-related renal functional decline. American Journal of Physiology 271(6 Pt 2):F1114–F1122.
- Frassetto, L., et al. 2018. Acid balance, dietary acid load, and bone effects—A controversial subject. Nutrients 10(4):517. Doi: 10.3390/nu10040517.
- Alves Carnauba, R., et al. 2017. Diet-induced low-grade metabolic acidosis and clinical outcomes: A review. Nutrients 9(6):538. Doi: 10.3390/nu9060538.
- Buclin, T., et al. 2001. Diet acids and alkalis influence calcium retention in bone. Osteoporosis International 12:493-499.
- Arnett, T. R. 2008. Extracellular pH regulates bone cell function. The Journal of Nutrition 138(2):415S-418S. Doi: 10.1093/jn/138.2.415S.
- Osuna-Padilla, I. A., et al. 2019. Dietary acid load: Mechanisms and evidence of its health repercussions. Nefrología 39(4):339-454. Doi: 10.1016/j.nefroe.2019.08.001.
- Adeva, M. M., and G. Souto. 2011. Diet-induced metabolic acidosis. Clinical Nutrition 30(4):P416-P421. Doi: 10.1016/j.clnu.2011.03.008.
- Aoi, W., et al. 2020. Body fluid pH balance in metabolic health and possible benefits of dietary alkaline foods. eFood 1(1):12-23. Doi: 10.2991/efood.k.190924.001.