Approximately one-quarter of the world's population (mostly women) will have a urinary tract infection (UTI) in their lifetime. Men tend to get UTIs when they grow older, but women are more susceptible because of the way they're built. A strong urge to urinate and a burning sensation when urinating are the most common symptoms of UTI. Antibiotics can help, but many who get UTIs have recurrent infections. That's because bacteria (mostly E. coli) form biofilms (slime) in the bladder that resist antibiotics and immune defenses.
There's a fascinating podcast online on how the body prevents UTI. The battle in your bladder is all about keeping iron levels to a minimum so bacteria cannot grow and produce biofilms. My anti-biofilm agents (bismuth thiols) also work by disturbing iron metabolism in bacteria, but that's another story.
It's been known for some time that humans produce an iron chelator (scavenger) called siderochelin that ties up iron in the urinary tract to protect against disease. But women with cystitis (bladder infections) have elevated levels of siderochelin, so apparently this iron chelator is not sufficient to stop UTI.
It turns out that two other factors need to be present to effectively keep iron away from E. coli. A new study in the Journal of Biological Chemistry (Shield-Cutler et al, 2015) showed that we also need to keep our urine at a reasonably high pH (a pH of 6 is too low, but 6.8 is effective). The pH in human urine ranges between 5.5 and 7.4, depending on the diet. Secondly, we need to produce high levels of what are called aryl alcohols in the urine to fully protect our bladders from infection. These substances are known to make urine smell strong. Aryl alcohols are likely produced from several food substances. They are metabolites from healthy diets, particularly those that contain compounds called proanthocyanidins (PACs). Aryl alcohols may also be derived from aromatic amino acids in protein, such as L-phenylalanine.
PACs are a class of polyphenols found in a variety of plants, including pine bark (Pycnogenol), grape seeds and skin, wine, apples, cinnamon, and chocolate. Bilberry, cranberry, black currant, green and black tea also contain these flavonoids. It is not clear which of these food items produce the most or best aryl alcohols in urine, but it's likely that many of them do.
It's particularly interesting that cranberry is on this list, since it is known to be a remedy for UTI. Cranberries help prevent biofilms by making it hard for bacteria to take hold in the urinary bladder. However, cranberries don't seem to work for everyone. It may be that other factors like urine pH need to be ideal for cranberries and other PACs to work efficiently.
With all the acid-forming foods in our diets, it is hard to keep the pH of the urine at a high level. Most protein, carbs and fats are acid-forming and must be balanced with non-starchy plant foods to increase urinary pH. The best way to maintain a high urine pH is to consume lots of alkaline-forming foods. Here's a list of the most extreme alkaline formers:
Apollinaris water, Asparagus, Blackberries, Burdock root, Cantaloupe, Celery, Chestnuts, Collard greens, Endive, Ginger, Horseradish, Kale, Kiwi, Kohlrabi, Lemon juice, Limes, Lotus root, Mangos, Mandarin oranges, Miso, Tamari (fermented soy), Mustard greens, Onion, Papaya, Paprika, Parsley, Parsnip, Persimmon, Pineapple, Pumpkin seeds, Radish (also Daikon), Raspberries, Rutabaga, Sanfaustino water, San Pelligrino water, Sea salt (unrefined, grey), Seaweed, Strawberries, Sweet potato, Yams, Tangerines, Tarot root, Apple Cider vinegar (also Umeboshi), Vegetable juice (non-tomato), Watermelon.
Another way to quickly bring up the pH of urine is with the use of bicarbonates. The common one is bicarbonate of soda (Baking soda), but it's loaded with sodium. The preferred form for this purpose is potassium bicarbonate (obtainable from nuts.com), since potassium is an important nutrient, especially for bone health, that we don't get enough of. As little as 1/8th of a teaspoon can raise urine pH substantially, and a 1/4 tsp may raise it to ideal levels. (I place 1/8th of a tsp in a large glass of water, once or twice daily.) The total amount of potassium amounts to 200-500 mg, which is only about 5-10% of the daily requirements for this vital nutrient. It's possible to measure the effect one hour afterward with pH strips available for this purpose. There are also powders sold in health food stores to help increase urine pH and restore bone health.
One note of caution with bicarbonates: The problem is getting thru the stomach, which is supposed to stay acidic to digest food and to ward off ulcers. So use them wisely (at least 30 minutes before eating, or at least 2 hours after eating). If you have ulcer issues, or they appear to upset your stomach, back off and use less. That's why I recommend small amounts at a time.
Interestingly, some of the foods that make your urine pH more alkaline are also foods that can provide more aryl alcohols in the urine. It all really comes down to eating a healthy diet but, for those with UTI problems, a super healthy diet may be required.
The Battle In Your Bladder. http://schaechter.asmblog.org/schaechter/2015/07/this-week-in-microbiology-107-the-battle-in-your-bladder.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed:+schaechter+(Small+Things+Considered)
Shields-Cutler RR, Crowley JR, Hung CS, et al. Human Urinary Composition Controls Antibacterial Activity of Siderocalin. JBC 2015. http://www.jbc.org/content/290/26/15949
Proanthocyanidin supplement health benefits, the right dosage to take for good health maintenance, by Ray Sahelian, M.D. Feb 14 2014. http://www.raysahelian.com/proanthocyanidins.html
Proanthocyanidin. Wikipedia. https://en.wikipedia.org/wiki/Proanthocyanidin