Alkaline water: Is it better for your body?

Dear Alice,

My friend recently bought a water filter. It's purpose is to raise the tap water's pH-level to alkaline level. She claims that alkaline water is good for our bodies because it reduces the acid level in our bodies. Is it true that waters with high alkaline (pH) level are really healthy for the human body? She paid $1000 for this water filter. Is it worth it? Please let me know soon if it's actually good for me, I'm thinking of purchasing one.

Dear Reader,

Filtered water seems to be all the rage these days — your friend isn't alone in her enthusiasm for filters of all types. Filter manufacturers make claims that alkaline water, which has a higher pH than regular tap water, will speed up metabolism to help you lose weight, slow the aging process, and even prevent cancer and heart disease. While studies have shown an association of alkaline water with decreased bone loss and age-related factors, not enough research has been done on alkalizing water filters to know how effective they are in improving a range of health concerns long-term.

pH is a measurement of acidity and alkalinity (also known as basicity) on a scale of 1 to 14. Substances with a pH under 7, such as orange juice, are considered acidic, while substances with a pH over 7 are considered alkaline. Alkaline waters tend to have a pH ranging from 8 to 9, while normal blood pH ranges between 7.35 and 7.45. This pH is carefully maintained by robust systems of the body that are unlikely to be significantly altered by alkaline water.

Calcium from bones helps to regulate the acidity or alkalinity of the blood. When the blood becomes too acidic from a diet high in refined sugar, flour, dairy, and meat, the body’s system works to draw calcium from the bones to bring the blood's pH back into the normal range. If the blood stays alkaline from a diet rich in fruits and vegetables (or from alkaline water, as the filter manufactures claim), the bones don't need to cede their calcium to the blood. This research supports the theory that calcium retention in the bones rather than in the blood will make bones denser and stronger. In addition to the potential benefits of alkaline water, researchers have found that eating a low-acid diet, that is, a diet full of fruits and vegetables and lower in animal protein and grains than the typical American diet, may lead to stronger bones.

Scientists have also shown a potential benefit of alkaline water on longer lifespans, though the research has been performed in mice and not humans. The theory is that the alkaline water prevents aging by reducing the amount of “free radicals” in the bloodstream. Free radicals, also known as reactive oxygen species, are harmful oxygen molecules that may cause damage to cells that then promotes aging. A more established method to combat free radicals is through consumption of antioxidants. Antioxidant rich foods include nuts, berries, kale, and even dark chocolate. If you find yourself concerned about the aging effects of free radicals, it may be more beneficial to avoid smoking, pollution, and excessive sunlight, rather than invest in an alkaline water filter, as those exposures are well-established sources of reactive oxygen species.

Whether your friend would like to try to raise her blood alkalinity by shelling out for a filter is up to her. If you don't have extra money to drop on a filter that may or may not be effective but are concerned about keeping the pH of your blood in check, you could try to increase your consumption of low-acid, antioxidant rich foods and shave down your intake of refined sugars, flours, dairy, and meat. Also, by drinking the recommended eight 8-ounce glasses a day, even if it’s of tap water, your hydrated organs can function well to balance the blood’s pH on its own. And if you’re still curious about alkaline water, fill up a water bottle or two at your friend’s house!

Last updated Sep 25, 2023
Originally published Jun 09, 2006

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