Want to make coffee less acidic? Add cream to it

The table below is from a 2008 article by Ehlen and colleagues (), showing the amount of erosion caused by various types of beverages, when teeth were exposed to them for 25 h in vitro. Erosion depth is measured in microns. The third row shows the chance probabilities (i.e., P values) associated with the differences in erosion of enamel and root.

As you can see, even diet drinks may cause tooth erosion. That is not to say that if you drink a diet soda occasionally you will destroy your teeth, but regular drinking may be a problem. I discussed this study in a previous post (). After that post was published here some folks asked me about coffee, so I decided to do some research.

Unfortunately coffee by itself can also cause some erosion, primarily because of its acidity. Generally speaking, you want a liquid substance that you are interested in drinking to have a pH as close to 7 as possible, as this pH is neutral (). Tap and mineral water have a pH that is very close to 7. Black coffee seems to have a pH of about 4.8.

Also problematic are drinks containing fermentable carbohydrates, such as sucrose, fructose, glucose, and lactose. These are fermented by acid-producing bacteria. Interestingly, when fermentable carbohydrates are consumed as part of foods that require chewing, such as fruits, acidity is either neutralized or significantly reduced by large amounts of saliva being secreted as a result of the chewing process.

So what to do about coffee?

One possible solution is to add heavy cream to it. A small amount, such as a teaspoon, appears to bring the pH in a cup of coffee to a little over 6. Another advantage of heavy cream is that it has no fermentable carbohydrates; it has no carbohydrates, period. You will have to get over the habit of drinking sweet beverages, including sweet coffee, if you were unfortunate enough to develop that habit (like so many people living in cities today).

It is not easy to find reliable pH values for various foods. I guess dentistry researchers are more interested in ways of repairing damage already done, and there doesn't seem to be much funding available for preventive dentistry research. Some pH testing results from a University of Cincinnati college biology page were available at the time of this writing; they appeared to be reasonably reliable the last time I checked them ().

Those daily extra cups of joe not linked to hypertension

An extra shot of espresso can surely help wake you up in the morning, but what does it mean for your blood pressure? It is well known that coffee's caffeine content can raise blood pressure temporarily, especially in people who have hypertension. Could habitually drinking high amounts have long-term effects on blood pressure too?

Java lovers will rejoice in a large study's findings that more cups daily isn't associated with increased risk of hypertension. The study, published in American Journal of Clinical Nutrition on March 30, was a systematic review and meta-analysis that examined six prospective cohort studies.

Two previous meta-analyses of randomized controlled trials found an association with slightly raised risk of hypertension. But these trials all lasted only 85 days or fewer days. In the new study, a total 172,567 participants and 37,135 incident cases of hypertension were followed over the course of six years.

Four of the six studies evaluated reported a nonlinear association between coffee consumption and hypertension, whereas two reported no statistically significant association. The pooled results revealed a relative risk of 1.09 (1.01; 1.18) from drinking 1 to 3 cups daily (a slightly elevated risk), 1.07 (0.96, 1.20) from drinking 3 to 5 cups daily, and 1.09 (0.96, 1.21) from drinking five or more cups daily.

The researchers suggested that the results of the study may be explained by coffee drinkers developing a tolerance to caffeine's acute effect on blood pressure, which is thought to be result of caffeine's binding to receptors that trigger a sympathetic nervous system response.

Additionally, another explanation may be that other ingredients in coffee like magnesium, potassium, or flavonoids could have a counterbalancing effect on blood pressure, which the researchers suggest may explain an inverse "J-shape" relationship between habitual coffee drinking and hypertension risk.

Since the way people metabolize caffeine in the liver can depend on genetics, the authors suggest more research is needed to determine coffee's effects on non-white populations.

Reference

Zhang Z, Hu G, Caballero B, Appel L, and Chen L. 2011. Habitual coffee consumption and risk of hypertension: a systematic review and meta-analysis of prospective observational studies1–3. Amer J Clin Nutr. doi: 10.3945/ajcn.110.004044.