The "Basics" of the Alkaline Diet
Question: What’s the fastest way to increase the cost of a bottle of water?
Answer: Add some common minerals to raise the pH and slap “Alkaline Water” on the label.
So is $10 per gallon (no really - Google “alkaline water”) really worth it?? I’m happy today to help unravel this mystery…
What is the Alkaline Diet?
The word “alkaline” is synonymous with “base,” which is the opposite of acid on the pH scale. The Alkaline Diet also goes by the name of the Alkaline-Ash Diet and is based on how different foods affect the pH of the blood.
To understand the alkaline diet, one first needs a basic understanding of pH. So bear with me a moment and put your chemistry caps on.
WTF is pH?
“pH” stands for “Potential of Hydrogen.” It’s literally a measure of how many hydrogen ions (H) there are in a measure of liquid. pH is measured on a scale of 0 to 14: lower numbers are more acidic and higher numbers are more basic.
In the body pH varies in different locations: gastric acid is pH around 1-3, whereas blood pH is tightly maintained between 7.35 - 7.45 pH (8, 13, 14). The varying pH levels serve different functions:
A very low pH in the stomach causes proteins to unravel. The very acidic environment of the stomach is our body’s first defense against food-borne illnesses, unraveling (most of, hopefully) the viruses and bacteria that are consumed (8)
Blood pH is very close to neutral; to become too acidic would mean our body’s own proteins would start to unravel (which is bad, in case you were wondering).
Because of the importance of maintaining appropriate pH, the body goes to great lengths to correct any imbalances. When blood pH starts to drop too low the lungs and the kidneys excrete acidic CO2 and Hydrogen ions, respectively, to bring pH back to normal (13).
How the Diet affects the Body’s pH
Contrary to what you might think, the acidity of a food doesn’t actually have anything to do with the effect that food has on the acid-base balance of the body. Rather it’s what’s in the food that makes a difference (7, 8, 12).
The nutrients potassium, magnesium, calcium, and bicarbonate are alkaline, so foods containing lots of these nutrients (fruits, veggies, and mineral water) have a net basic effect on the body. Foods high in protein and phosphorus (meat, cheese, soda) have a net acidic effect on the body (1, 2, 8, 12, 13, 14, 15, 18). This means even though a lemon tastes very acidic, it actually has a net alkaline effect on the body.
The acid-base balance in the blood is a little like a teeter-totter. To make the blood more alkaline, one could:
Add potassium, magnesium, calcium, or bicarbonate to the diet
Excrete more CO2 by breathing harder
Excrete more Hydrogen (H) ions in the urine
Reduce protein and phosphorus in the diet
A Brief History of the Alkaline Diet
Recently, alkaline diets and specific products promoting alkalinity, such as alkaline water, have become popular. Marketers claim consuming an alkaline diet is the antidote to the current acidic “Western” diet. They claim alkalinity is the answer to the prevention of cancer, osteoporosis, and cardiovascular disease (6, 7, 8, 13).
The “typical” Western diet (high in meat, cheese, and grains; low in fruits and veggies) has a net acidic effect on the body (8, 12). In the short term this is no big deal because the kidneys are getting rid of those excess Hydrogen (H) ions by excreting them into the urine. Thus, blood pH only fluctuates up or down 0.01 - 0.03 pH units, but the urine pH can fluctuate up to 1.0 pH unit depending on how many H ions the kidneys have to remove (2, 6, 7, 12, 14).
With age and a higher diet acid load the kidneys become less able to regulate pH; long-term an acidic diet could be harmful to health by contributing to slight metabolic acidosis (8, 14). Mild blood acidosis has been linked to changes in Growth Hormone and Insulin-Like Growth Factor, both of which can cause cardiac dysfunction (12, 14). Acidosis may also cause insulin resistance and impaired thyroid hormone secretion, but further study is needed to understand these connections (15, 17, 18).
The theory goes that by reducing acid-forming foods in the diet (meat, cheese) and increasing alkaline-forming foods (fruits, vegetables) one can correct the minor metabolic acidosis and improve health.
How the Alkaline Diet Works
The alkaline diet doesn’t necessarily have anything to do with weight, but there are many claims how this diet affects a variety of different aspects of health.
Perhaps you’ve heard of lactic acid build-up with anaerobic exercise. In anaerobic exercise a person exercises faster than glucose can fully break down because of a lack of sufficient oxygen. This anaerobic metabolic process leaves behind lactic acid and - you guessed it - lactic acid is acidic.
Remember: the body maintains very tight blood pH levels, so when lactic acid starts to build up in the blood a person starts to exhale more carbon dioxide. Carbon dioxide, or CO2, is found on the “acid” side of the scale, so getting rid of CO2 helps return the blood to alkalinity. However there comes a point of exercise when a person can’t get rid of enough CO2 fast enough - and thus a person reaches their maximum exercise capacity.
There is a hypothesis that if there were another buffer to help neutralize some of the lactic acid, a person could increase his maximum exercise potential. Remember the teeter-totter: if lactic acid builds up, something on the opposite side of the teeter-totter would help to bring it back to neutral.
Some studies show athletes who regularly consume a more alkaline diet have increased capacity for maximal (anaerobic) exercise, with a dose-dependent relationship: the more alkaline the diet, the higher the max exertion (2, 12). Additionally, a long-term alkaline diet may improve performance in aerobic endurance sports such as marathon running by helping the body burn fat instead of carbohydrate, since carbohydrate stores are depleted by the end of the race (2), but this effect is not associated with acid-buffering as in anaerobic exercise (12).
Another hypothesis which has been tested is to consume alkaline water or a different type of mineral buffer before or during exercise, which is known as “bicarbonate loading.” The hypothesis is a bicarbonate dose of 0.3 - 0.5g/kg body weight may help the body neutralize the lactic acid more efficiently. This in theory would yield an increase in maximum exercise capacity in short, intense intervals lasting 1-4 minutes such as a sprint (2, 3, 11). However studies are mixed and even in the same person with the same bicarbonate dose the results are not consistent (19).
Bottom line: if you’re an elite athlete engaging in short-duration anaerobic exercise, alkaline water or bicarbonate loading might give you a very small advantage, but this has not been consistently proven (and beware of the GI distress that may occur) (2, 3, 11, 19). Untrained athletes don’t see this same effect, so if you’re not an elite athlete don’t worry about the fancy supplements (11). Instead focus on a diet full of fruits and veggies which may increase the body’s capacity to buffer lactic acid build-up, but is also generally healthy (2).
Chronic Kidney Disease
As mentioned previously, one of the jobs of the kidneys is to aid in acid-base balance by getting rid of extra Hydrogen ions (that’s the H in pH) (13). This is why an acidic diet won’t affect the pH of the blood very much but it will affect the pH of the urine. However if the kidneys are damaged and unable to filter enough H ions out of the blood, a very acidic diet can start to change pH of the blood and cause metabolic acidosis (1, 12, 13, 15, 18).
Dietary acid load and chronic metabolic acidosis are risk factors for the development and progression of Chronic Kidney Disease (CKD) (13, 15). Supplementing fruits and vegetable even in advanced stages of kidney disease has been shown to protect kidneys from further damage (1, 13, 15, 18). Adding bicarbonate can help reduce the acid load, but over-supplementation can also be dangerous and so should be closely monitored (15, 18).
Bottom line: an alkaline diet with moderate protein intake (0.8 - 1.0 grams per kilogram body weight) PLUS lots of fruits and vegetables appears to protect the kidneys (1, 15, 18).
Some laboratory studies show cancer cells and tumors grow better in an acidic environment, which is perhaps where the idea of an alkaline diet to treat or improve cancer outcomes originated (7, 8). Additionally, some types of chemotherapy require a higher pH, so a hypothesis exists that an alkaline diet could be beneficial to some types of cancer treatment (14). However, as mentioned before, blood pH changes very minimally and so the actual effect on cancer is minimal (7).
Unfortunately scientific literature on the subject of alkaline diet and cancer in humans is very minimal at this time (10, 14). A recent meta-analysis identified only one valid study to review, which showed a slightly elevated risk for bladder cancer with an acidic diet, but even this risk was minimal when compared with the increased risk of smoking on bladder cancer (7). It’s possible that some of the claims of the benefits of the alkaline diet are related to the overall quality of diet with the increase in fruits and vegetables. Otherwise no studies exist for the effect of the alkaline diet or alkaline water on either cancer risk or cancer treatment (7, 10).
Bottom line: There is little to no scientific evidence to support an alkaline diet or alkaline supplements for the prevention or treatment of cancer (7, 10, 14).
Because calcium is an alkaline mineral, it has been thought that a high-acid diet would cause the body to leach calcium from bone to balance blood pH and thus lead to bone loss (6, 8, 9, 14). Indeed, high dietary protein intake is associated with an increased urinary calcium, but this is not necessarily representative of bone calcium depletion (6, 8, 9).
The highest-quality studies show no evidence that diet affects calcium balance in healthy humans with normal kidney function. Even diets high in protein do not appear to cause calcium depletion because dietary protein increases calcium absorption in a quantity similar to the rise in urine calcium (6). Some observational studies link higher intake of fruits and vegetables with decreased bone loss, but evidence to this and the benefit of an alkaline diet in general is mixed (6, 7, 14).
Bottom line: There is little to no scientific evidence supporting alkaline supplements or alkaline diet preventing osteoporosis (6, 9).
Precautions to Take with the Alkaline Diet
Generally the Alkaline Diet is in line with other proven nutrition guidelines: it’s healthy to consume a moderate amount of protein and grains with a large amount of fruits and vegetables in the diet. Thus the precautions to take with this diet are minimal and only relevant in a couple of circumstances.
Chronic Kidney Disease
In advanced stages of chronic kidney disease (CKD) some patients must limit their intake of potassium. Because of this, an alkaline diet high in fruits and vegetables can put someone with CKD at risk for hyperkalemia (high blood potassium levels) unless carefully monitoring their diet (18).
For most people with mild kidney damage increasing fruits and vegetables is still encouraged, but if you have CKD, talk with your doctor or dietitian before switching to an alkaline diet.
Like I said up front - go do a quick Google search for “Alkaline Water.” You’ll quickly find that the biggest risk of an alkaline diet is to your bank account.
But purchasing fancy-pants alkaline water is not necessary unless you’re competing as a sprinter in the summer Olympics. Instead go roast some fresh veggies (check out Miller Farms if you need a local source in Colorado) and go easy on the portion of steak.
Alkaline Diet: Overall Grade
Weight Loss: Grade C
Maintenance: Grade A-
Consuming an alkaline diet is more about quality and overall health than it is about weight loss. However, if a person transitions from consuming acidic calorie-dense foods (meat, cheese) and in place of these increases the amount of alkaline calorie-poor foods (vegetables, fruits), gradual weight loss may occur.
“Maintenance” gets an A rating because this diet is all about balance. It’s not meant to be extreme or cut out entire food groups but is rather about increasing the proportion of produce as compared to meat and cheese in the diet.
“Maintenance” was downgraded to an A- rating because this type of diet is not how most Americans eat. It’s difficult to find this balance if you don’t cook at home and find yourself eating a lot of processed food.
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