Can you please tell me about the benefits of drinking water as well as provide me with some information about its pH balance?
First, with respect to the benefits of drinking water, I cannot overemphasize the importance of this essential nutrient. Our bodies are approximately 60% water by weight, and even a 5% shift in this amount can compromise our health. Our bloodstream cannot transport nutrients effectively unless we drink enough water. Our kidneys cannot filter wastes without enough water. We cannot maintain our skin tone, or our digestive flow, or regulate our body temperature without enough water. The vast majority of nutrients dissolve in water, and this fact alone makes water unique in our nourishment.
The natural pH of water is close to neutral-a measurement of 7 on the pH scale. Water districts typically try to keep the pH of tap water within a limited range of 6-10. I've seen websites recommending consumption of "acidified water" in which an acid substance is added to natural water to bring its pH level down. I've also seen websites recommending consumption of "alkalized water" in which a basic substance is added to raise water's natural pH. I've never seen research studies to suggest that either practice is desirable. In addition, these steps don't make sense to me from a science standpoint. One of the unique features of water is its neutral pH-this neutral level allows the body to easily shift the pH either up or down, depending on the moment-by-moment metabolic circumstances. In most circumstances, the optimal step is to support the body's ability to carry out metabolic activities by consuming adequate amounts of clean, neutral pH water, and leaving the acid-base balance up to the body and its complex buffering systems.
At a much more general level, two factors are equally important when it comes to water: (1) drinking a sufficient amount, and (2) making sure what you drink is high quality.
The quality of tap water can vary depending upon where you live and whether the water is provided from a municipal site or you have your own spring or well. Contamination can occur not only from the water source but also from sources closer to home. For example, the quality of your water can be affected by your type of plumbing (whether you have copper lined pipes, lead solder containing plumbing, etc.), whether you use a well, and whether there is contamination from agricultural chemicals. If you are curious about the quality of your water, you may want to get it tested. In general, it would be best to filter city water before consumption. With rural (well) water, the decision about filtering is usually best made on a well-by-well basis.
The quality of bottled water also varies greatly. Some water is good quality and other water is simply repackaged tap water. Bottled water can also be expensive, unless purchased in large amounts in the type of 5-gallon containers used with water coolers often found in office settings. I recommend that you read the label carefully when buying bottled water and look for the following information:
If you are concerned about the quality of your tap water, you may want to investigate getting a water filter. In general, the best water filters involve blocks of carbon (rather than granulated carbon) and are often combined with reverse osmosis filters. The under-sink types of filters are typically more effective than the type that attach at the faucet. I recommend carbon block or reverse osmosis filters over distilled water because I believe that too many desirable minerals are lost during the process of distillation. Another option that may be available in your area is water filtration systems in supermarkets. Many natural foods supermarkets offer good quality water filtration systems where you can refill your own jugs. For some this is a convenient option, yet for others having a home filtration system is more convenient.
Whatever option you use for guaranteeing high quality water, you also need to make sure that you consume enough water during the course of the day. Water is usually best consumed between meals if you are drinking a sizable amount (8 ounces or more). As for intake goals, the National Academy of Sciences recommends (in its Dietary Reference Intake (DRI) recommendations) about 13 cups of water each day for men and 9 cups for women.
The issue of acid and alkaline foods is a confusing one, because there are several different ways of using these words with respect to food.
The pH of foods
In food chemistry textbooks that take a Western science approach to foods, every food has a value that is called its "pH value." pH is a special scale created to measure how acidic or alkaline a fluid or substance is. It ranges from 0 (most acidic) to 14 (most alkaline) with 7.0 being neutral. One way of thinking about it is that as you get closer to 7.0 from either end, the food becomes less acidic (6.0 vs 5.0, for example) or less alkaline (8.0 vs 9.0, for example).
Limes, for example, have a very low pH of 2.0 and are highly acidic according to the pH scale. Lemons are slightly less acidic at a pH of 2.2. Egg whites are not acidic at all, and have a pH of 8.0. Meats are also non-acidic, with a pH of about 7.0.
Many vegetables lie somewhere in the middle of the pH range. The pH of asparagus, for example, is 5.6; of sweet potatoes, 5.4; of cucumbers, 5.1; of carrots, 5.0; of green peas, 6.2; of corn, 6.3. Tomatoes fit on the pH scale toward the more acidic end in comparison to other vegetables. Their pH ranges from 4.0 to 4.6. However, this range is still higher (less acidic) than fruits like pears (with a pH of 3.9) or peaches (with a pH of 3.5) or strawberries (3.4) or plums (2.9).
Acid-forming foods
Another way to talk about food acidity is not to measure the acidity of the food itself, but the to measure changes in the acidity of body fluids once the food has been eaten. In other words, from this second perspective, a food is not labeled as "acidic," but instead as "acid-forming."
Although the idea of acid-forming foods goes back almost 100 years in the research, there's been very little research published in this area until fairly recently. In earlier publications, acid-forming foods were often talked about as key components of an "acid-ash diet." The term "ash" was used much more commonly in those days to refer to the inorganic components of a diet (mineral elements or molecules not containing carbon) that remained after the digestion and metabolism of food had occurred. This ash was also commonly referred to as a "residue" of the diet. Diets largely devoid of meat, fish, eggs, cheese, and grains were described as "alkaline-ash diets." These diets focused on consumption of fruits and vegetables and also included cow's milk. By contrast, diets containing large amounts of meat, fish, eggs, cheese and grains were described as "acid-ash diets."
Although the term "ash" is seldom used in current research studies on diet, the idea of acid-forming foods has remained a topic of research interest. A new term has been created in the research world to refer to the potential impact of certain foods on the kidneys and urine acid levels. This term is "potential renal acid load" or PRAL. For meats, a PRAL value of 9.5 has been reported by researchers. Alongside of meats in terms of high PRAL value are cheeses (8.0), fish (7.9), flour (7.0), and noodles (6.7). In contrast with these high PRAL values are the values for fruits (-3.1), vegetables (-2.8), fruits, and cow's milk (1.0).
Researchers have been concerned about one particular aspect of high-PRAL food intake, and that concern involves bone health. It's always important for our bloodstream to keep acidity under control. Our kidneys, lungs, and other organ systems work hard to keep our blood pH very close to 7.4. However, if presented with too many acids from the digestion and metabolism of food, our body will try to neutralize those acids using a process called buffering. To buffer an acid, our body needs to link the acid with another chemical called a "base." Sodium, potassium, calcium, and magnesium are minerals that readily form bases for our body to use as acid buffers. One readily available source for calcium is bone, and researchers have wondered whether a diet that is overly acid-forming will place too heavy demands on our bone for calcium buffers. There's some research that suggests this process may take place over the short run (60 days or less), but the long-term impact of excess acid-forming foods in the diet on bone calcium is not clear from studies to date.
One of the factors that high-PRAL foods have in common (with the exception of grains) is their high protein content. Meat, fish, and cheese are all high-protein foods. Because protein is composed of amino acids, and because amino acids can be easily converted in the body to organic acids, it makes sense for high-protein foods to be treated as foods that can increase potential renal acid load. When present-day researchers try to model the potential acid-forming nature of a diet (meaning the potential for a diet to increase the acidity of our urine and acid load upon our kidneys), they always factor in the protein density of the diet. Potassium content, calcium content, and magnesium content are also typically factored in because these minerals readily form bases that can be used to help buffer acids. Sometimes researchers also look at the ratio of a potentially acid-forming component like protein to an available buffering mineral like potassium.
The table below summaries primary higher PRAL and lower PRAL food groups
| Food Group | PRAL | Higher or Lower PRAL | |
|---|---|---|---|
| Meats | 9.5 | Higher | |
| Cheeses | 8.0 | Higher | |
| Fish | 7.9 | Higher | |
| Flour | 7.0 | Higher | |
| Noodles | 6.7 | Higher | |
| Fruits | -3.1 | Lower | |
| Vegetables | - 2.8 | Lower | |
| Cow's Milk | 1.0 | Lower |
Source: Barzel US and Massey LK. (1998). Excess dietary protein can adversely affect bone. J Nutr 128: 1051-1053.
Acid-alkaline and the World's Healthiest Foods
Although the impact of foods on our kidneys and urine acidity is definitely an important topic from the standpoint of diet and health, it is still one very narrow component of our body's acid-base balance. All of our bodily fluids have their own characteristic degree of acidity, and our metabolism works in thousands of ways to protect acid-base levels in all of our tissue. So we would not want to draw any hard and fast conclusions about how to eat from studies on urine acidity and the PRAL value of foods. However, I do believe that research in this area supports our basic approach to healthy eating at the World's Healthiest Foods. We place our greatest emphasis on daily intake of vegetables and fruits, and in this urine acidity research, we discover that vegetables and fruits have lower PRAL values than any other food groups. We also encourage moderation throughout our website with respect to consumption of meats and believe this recommendation is in keeping with urine acidity research that places meats at the top of the PRAL list with a value of 9.5. While the PRAL research was not a factor in our initial construction of the World's Healthiest Foods list, we are reassured to see that our Healthiest Way of Eating is one that should result in little risk with respect to potential renal acid load.
Other approaches to acid-alkaline and diet
On other websites, especially websites interested in macrobiotic eating, Asian medicine, and energy medicine, you'll find detailed discussion of acid-forming and alkaline-forming foods that do not follow this Western science research involving urine acidity and PRAL values. Instead, these approaches typically look at whole body acid-base balance (rather than acidity of one body fluid like the urine) and they talk about "toxic acidic conditions" or the need for a slightly alkaline condition in the body as whole. To find out more about these alternative ways of approach acid-base balance in the body and dietary choices, you may want to visit one or more of the following websites:
http://www.gomf.macrobiotic.
http://www.kushiinstitute.org/
http://www.ppnf.org/catalog/
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