1. Dietary Acid Load Associated with Hypertension and Diabetes in the Elderly
Tulay Omma, Nese Ersoz Gulcelik, Fatmanur Humeyra Zengin, Irfan Karahan, Cavit Culha Curr Aging Sci. 2022 Aug 4;15(3):242-251. doi: 10.2174/1874609815666220328123744.
Background: Diet can affect the body's acid-base balance due to its content of acid or base precursors. There is conflicting evidence for the role of metabolic acidosis in the development of cardiometabolic disorders, hypertension (HT), and insulin resistance (IR). Objective: We hypothesized that dietary acid load (DAL) is associated with adverse metabolic risk factors and aimed to investigate this in the elderly. Methods: A total of 114 elderly participants were included in the study. The participants were divided into four groups, such as HT, diabetes (DM), both HT and DM, and healthy controls. Anthropometric, biochemical, and clinical findings were recorded. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) results were obtained for three days, 24-hour dietary records via a nutrient database program (BeBiS software program). Results: The groups were matched for age, gender, and BMI. There was a statistically significant difference between the groups regarding NEAP (p =0.01) and no significant difference for PRAL ( p = 0.086). The lowest NEAP and PRAL levels were seen in the control group while the highest in the HT group. Both NEAP and PRAL were correlated with waist circumference (r = 0,325, p = 0.001; r=0,231, p =0,016, respectively). Conclusion: Our data confirmed that subjects with HT and DM had diets with greater acid-forming potential. High NEAP may be a risk factor for chronic metabolic diseases, particularly HT. PRAL could not be shown as a significantly different marker in all participants. Dietary content has a significant contribution to the reduction of cardiovascular risk factors, such as HT, DM, and obesity.
2. Free lactic acid production under acidic conditions by lactic acid bacteria strains: challenges and future prospects
Mamata Singhvi, Takeshi Zendo, Kenji Sonomoto Appl Microbiol Biotechnol. 2018 Jul;102(14):5911-5924. doi: 10.1007/s00253-018-9092-4. Epub 2018 May 26.
Lactic acid (LA) is an important platform chemical due to its significant applications in various fields and its use as a monomer for the production of biodegradable poly(lactic acid) (PLA). Free LA production is required to get rid of CaSO4, a waste material produced during fermentation at neutral pH which will lead to easy purification of LA required for the production of biodegradable PLA. Additionally, there is no need to use corrosive acids to release free LA from the calcium lactate produced during neutral fermentation. To date, several attempts have been made to improve the acid tolerance of lactic acid bacteria (LAB) by using both genome-shuffling approaches and rational design based on known mechanisms of LA tolerance and gene deletion in yeast strains. However, the lack of knowledge and the complexity of acid-tolerance mechanisms have made it challenging to generate LA-tolerant strains by simply modifying few target genes. Currently, adaptive evolution has proven an efficient strategy to improve the LA tolerance of individual/engineered strains. The main objectives of this article are to summarize the conventional biotechnological LA fermentation processes to date, assess their overall economic and environmental cost, and to introduce modern LA fermentation strategies for free LA production. In this review, we provide a broad overview of free LA fermentation processes using robust LAB that can ferment in acidic environments, the obstacles to these processes and their possible solutions, and the impact on future development of free LA fermentation processes commercially.
3. The Stephan Curve revisited
William H Bowen Odontology. 2013 Jan;101(1):2-8. doi: 10.1007/s10266-012-0092-z. Epub 2012 Dec 6.
The Stephan Curve has played a dominant role in caries research over the past several decades. What is so remarkable about the Stephan Curve is the plethora of interactions it illustrates and yet acid production remains the dominant focus. Using sophisticated technology, it is possible to measure pH changes in plaque; however, these observations may carry a false sense of accuracy. Recent observations have shown that there may be multiple pH values within the plaque matrix, thus emphasizing the importance of the milieu within which acid is formed. Although acid production is indeed the immediate proximate cause of tooth dissolution, the influence of alkali production within plaque has received relative scant attention. Excessive reliance on Stephan Curve leads to describing foods as "safe" if they do not lower the pH below the so-called "critical pH" at which point it is postulated enamel dissolves. Acid production is just one of many biological processes that occur within plaque when exposed to sugar. Exploration of methods to enhance alkali production could produce rich research dividends.
