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Adventures in Urinary PH: is the Alkaline Diet Scientifically Valid?

Article at a Glance
  • Blood PH is tightly regulated by the body, but urine and saliva PH vary greatly based on diet.
  • The PH of urine plays a role in the body’s ability to excrete waste products like uric acid.
  • More alkaline urine PH is associated with lower levels of uric acid in some studies.

Scientifically reviewed by Dr. Aaron Gardner

Yes, you read that right, I am regularly measuring the PH of my urine using special test strips.

I pee into a cup, dip in a PH strip and then match the color to the acid alkaline chart on the container.

Why am I doing this?

First and foremost, it’s a great topic for dates. There’s nothing the ladies like more than a man with alkaline urine.

Next, and this may come as a shocker, but I am not alone. Lots of people measure urine PH. Famous (and ageless) supermodel Elle MacPherson regularly checks the PH of her urine as part of her beauty regimen. Alas, I suppose checking urine PH is the only way I will make my way into the company of supermodels, but I digress.

Elle believes “most ailments are caused by an acidic body,” and Tom Brady is also way into the alkaline diet craze (Danielle even mimicked one of his alkaline smoothies in our recipe library). In response, medical professionals interviewed by various tabloid newspapers gleefully chime in dismissing the urine PH obsession as “pointless” and based on “junk science.”

Many others in the blogosphere have written at length about the “acid vs. alkaline myth.”

But is it a myth?

Like so much of the information in the health world, the alkaline diet is wildly oversold, but nevertheless, it does have a basis in science when applied to some narrowly tailored, yet very important health issues.

Although the notion of acidic blood caused by eating meat and “acid foods” leading to diseases like osteoporosis has been largely debunked, there are multiple science backed reasons to shoot for an alkaline PH in urine. The acid load of the blood is tightly regulated by the body, but the PH of the urine and saliva varies greatly based on what we eat.12 The state of the PH of both systems in turn has an influence on our health, especially if we are genetically predisposed to higher levels of uric acid, or if you are a woman suffering from urinary tract infections, or a man dealing with prostatitis.

Let’s jump into it, shall we?

Urine PH and Uric Acid

Uric acid is a waste product of purine metabolism.3 Purines are microscopic crystal compounds found in food, but also made by the body. In fact, we make 2/3rds of the purine found in our system, and get the rest from high purine foods like alcohol, beef, poultry, organ meats and seafood.

Some don’t metabolize purine as efficiently or quickly as others, which is one of the factors leading to different levels of uric acid in different people.

Although uric acid may be somewhat protective against certain diseases, such as Parkinson’s, high levels of uric acid are definitely a bad thing.45

At high enough concentrations, uric acid interferes with nitric oxide synthesis, and also acts to oxidize LDL. Brass tax: this is why a plant based diet can help some people lower blood pressure.67 Rapid metabolism of purine leads to high uric acid, which constricts nitric oxide depleted blood vessels, which makes the heart pump harder, which leads to hypertension.8

The oxidized LDL piece is bad for the heart because these damaged LDL particles damage endothelial cells when they deliver their  Frankenstein fats to the artery wall. High oxidized LDL is linked to heart disease.

But elevated uric acid isn’t just a purine issue, it can also be caused by drinking alcohol and eating sugar. In fact, the well known anti-aging doctor Peter Attia sees uric acid as a proxy for fructose metabolism, and aims to have all his patients below a level of 5.0 mg/dl. In his interview with Dr. Robert Lustig, which I would recommend listening to, Dr. Lustig describes high uric acid as a sign of “fructose bio-toxicity.” Dr. Lustig is a little less stringent and likes to see his patients with uric acid levels below 5.5 mg/dl.

So, we see that uric acid is a bad guy, and that levels are driven by protein metabolism as well as sugar in the diet. People whose uric acid levels get too high develop gout, a disease marked by painful joint pain.

And guess what?

The more acidic the urine, the harder it is for the kidneys to get rid of uric acid. When urine PH is alkaline, the body is able to excrete more uric acid in the urine, when it is is acidic, the kidneys hold on to the uric acid.

This study in Japanese women found that women fed a more alkaline diet (resulting in a urinary PH of 6.5) excreted about 25% more uric acid than a group fed a more acidic diet higher in purine (urinary PH of 5.9). Interestingly, even the alkaline group in the study still had a urine PH that would be considered acid by many.

I personally have been shooting for 6.75 and above.

Urine PH and Infection

The PH of urine and saliva dictate the types of bacteria that grow in the mouth and gut and similarly, the PH of urine plays a big role in whether pathogenic species of bacteria can take root in the body as well.

As I highlighted in my post on prostate health, a study that appeared in the Central Journal of Urology found that young men presenting with inflammation of the prostate were usually suffering from an undiagnosed fungal infection, and it was E. coli, a pathogenic strain of bacteria that acted as a “bridge” allowing fungal pathogens to make their way to the prostate. As part of the healing regimen, which saw an improvement rate of over 80%, the researchers had the men take potassium citrate, a potent agent for alkalizing urine. Research at Washington University in St. Louis, which looked at the cause of urinary tract infection, has demonstrated, E. coli cannot grow in alkaline urine.

In light of these findings, it would appear that keeping urine PH alkaline could help ward off prostate inflammation in men and urinary tract infection in women.

Health conditions improved by alkaline urine PH

We know that the “osteoporosis acidic blood” angle is out, what conditions are improved by a urine PH that is more alkaline?

I am not saying that the PH of urine is causative in all these cases, but for people paying attention to these conditions, urine PH can act as a rough barometer for gauging success.

High Blood Pressure and Heart Health

As we touched on above, if you are prone to elevated uric acid, your risk for heart disease goes up. Increasing urinary PH through dietary interventions would help improve blood pressure by allowing your body to get rid of more uric acid and therefore make more nitric oxide.

Gout, Arthritis, Joint Pain

This is an easy one. Gout is also caused by too much uric acid. Eating a low purine diet, which will have the effect of raising urine PH, will help to decrease symptoms. One of the standard treatments for rheumatoid arthritis is a gluten free vegetarian diet.9

Men’s health

In the last section, I explained how new research is demonstrating a link between urine PH and pathogenic bacteria in the urinary tract. But while we tend to view these conditions as binary, they often actually exist on a spectrum. For men, it’s not you either have prostate inflammation or you don’t, it’s really a sliding scale. Perhaps one of the mechanisms underlying better prostate health for men eating a diet that skews more plant based diet is a urine PH that repels the inflammation caused by pathogens that thrive in more acidic environments? Just as it’s the immune system response that damages the artery wall after an errant lipoprotein delivers cargo into the “sub endothelial” space, perhaps the same process occurs in the prostate? The pathogen load increases over time, which invites an immune response and the resulting inflammation enlarges the prostate over time. We do know that the immune system reacts in a pro inflammatory way to E. coli colonization.10

Urinary tract infections

Again, this is based on the research from Washington University in St. Louis who found that acidic urine allows for the growth of E. coli, which is one of the main culprits behind UTI.11

My Urine PH Test Results

When I looked at my own labs, I was surprised to see my uric acid levels at around 6.3-6.5 mg/dl historically. The lab I use, Boston Heart Diagnostics, listed this well in the green range (anything over 7.0 mg/dl is in the beginning of the trouble zone) so I’d never thought much about it, but based on the targets set by Dr. Attia and Dr. Lustug, it’s a metric I resolved to move below 5.5 mg/dl (and if I am being honest with myself, I do indulge in some pretty epic sugar bungee from time to time).

As such, I started testing my urine PH more to see how different foods moved the needle.

If you have any findings of your own regarding urinary PH, please share in the comments. Here is what I saw over the course of a few days. Maybe the biggest surprise for me was that coffee and espresso don’t appear to be acidic, to the contrary, they make my urine more alkaline.

It is important to note that as I share this data, I don’t know how long any one nutritional input takes to have an impact on urinary PH. The study on Japanese women I cite above found it took 3 days to get urine from an acid PH to a more alkaline PH, but inside of a day’s eating window, it’s not clear to me.

Nonetheless, below are some time windows I can share where PH moved a decent amount. Note that urinary PH is always lowest and most acidic in the mornings. For those of you playing along at home with your Gene Food diet types, I am in the Mediterranean category.

March 4

Wild salmon and black beans night before.
Urine on waking – 5.75-6
Immediately after eggs / blueberries / coffee – 6.75-7
Saliva PH – 8.5
Immediately after Americano – 8.0
Urine one hour after Americano and cream – 7.5
Dropped to 6.75 3 hours after breakfast of eggs and blueberries
After lunch of Brocolli and tofu plus brown rice – 7.0-7.25
Evening before dinner – 7.5
After pad Thai dinner and brocolli sprouts plus banana – down to 6.0

March 7

Waking PH after mezcal plus dinner of rice, beans, potatoes – 6.5
Two hours after americano with cream 7.5

March 10

Night before beans and rice, cauliflower and jackfruit tacos plus mezcal
5.75 urine morning
Breakfast of coffee, quercetin, mesclun greens, 1/2 banana, almond butter, hemp seed, almond milk smoothie (alkalizing Tom Brady Smoothie)  jumps to about 8.0
Sheep’s milk yogurt, eggs, green salad for mid morning snack heads down to 7.0

March 12

Night before wild salmon, purple potato, radishes, black bean burrito from Amy’s (processed), plus B vitamin complex.

Morning – 6.0

Then, after a breakfast of buckwheat porridge with almond butter and blueberries, stayed around 6 – 6.5.

Lunch brown rice, black beans and avocado – still at 6.5.

Coffee – stayed the same.

Green smoothie of broccoli sprouts, half a banana and pea protein. Went to 7.5.

Dinner of beans and rice and jack fruit tacos, plus tart cherry juice, a probiotic and magnesium supplement.

7.5 after dinner.

March 13

On waking this morning, March 13th, I was at 6.5 prior to breakfast. One of my most alkaline mornings yet.

PH went up to 7.25 after oats and espresso (1 regular, 2 decaf)

I haven’t had meat for 5 days at this point. Will be curios to see what various animal proteins do to PH.

Thoughts on my PH readings

After doing this experiment, I am not sure tracking urine PH from hour to hour means all that much, however, I will keep a urine PH above 6.5 as an overall goal moving forward.

I know that the consensus is that you will have more acidic urine in the morning, but I found this especially to be the case after drinking alcohol, big shocker.

I didn’t consume any meat during this period, just wild fish, so that could have explained why I rarely dropped below 6.5 during the day. A notable exception was a Pad Thai meal I had, so it seemed for me that refined grains were acidic on my system.

My sense of things is that certain supplements will have an acidifying effect on the urine, I believe this is the case with B vitamins. It’s also my hunch that prescription medications would lower PH.

For me, espresso is more alkalizing than is regular coffee. While you do see conflicting information online, the best study I have seen links coffee consumption, but not tea, with lower uric acid levels, so my results appear to make sense.12 It is worth noting here that it is not the caffeine which is thought to lower uric acid.

At the end of the day, while the hour to hour readings seem unnecessary over the long run, I think there is value in trying to keep urine PH at between 6.5-7.25 as these seem to the sweet spots based on the available research we have. An occasional reading in the morning and one later at night could be worthwhile, especially if your uric acid levels are tracking above 7.0 mg/dl or you’re looking for optimal performance in the model of Peter Attia.

Who knows, maybe Elle Macpherson and Tom Brady are on to something?

John O'Connor

John O'Connor is the founder of Gene Food. He is passionate about nutrition, genetics, and wellness and uses this blog to publish self experiments as well as some of the research that the Gene Food team does internally to highlight stories of bio-individuality.

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