What is an alkaline diet? Is it healthy?
The premise behind the alkaline diet (a.k.a. alkaline acid diet) is that certain foods including meat, eggs, dairy, grains as well as sugary and salty foods – staples of the North American diet – make the body acidic, which can lead to a host of health problems including weight gain, osteoporosis, arthritis, diabetes, heart disease, even cancer.
The diet emphasizes so-called alkaline foods such as fruit, vegetables, nuts, beans and lentils, which are believed to balance the body's natural pH level, making it less acidic. In so doing, proponents contend you'll have more energy, lose excess weight, boost immunity and fend off countless chronic diseases.
A pH level measures how acidic or alkaline something is (pH stands for "potential of Hydrogen"). The pH scale runs from 0 to 14 with 7 being neutral. Readings less than 7 indicate acidity (0 is totally acidic) while higher readings indicate alkaline.
The body's pH level varies considerably. Your stomach is acidic so it can digest food and protect against infection-causing microbes. Your blood is slightly alkaline with a pH between 7.35 to 7.45. Urine, on the other hand, can be acidic or alkaline depending on what you eat.
The goal of the alkaline diet is to maintain the pH level of your blood (alkaline). If you don't – because you eat too many acidic foods – your body will restore blood pH balance by robbing minerals from your bones (calcium, magnesium and potassium are alkaline). Proponents of the alkaline diet contend that's how our meat- and dairy-heavy diet causes osteoporosis.
The notion that diet can markedly change the pH of your blood goes against what we know about the body's chemistry. The human body naturally regulates a constant pH in the bloodstream. (Diabetes and kidney disease can cause problems with pH regulation.) There's not a stitch of evidence that any food – or diet – can substantially change blood pH. Clinical trials on the effectiveness of an alkaline diet for reducing health risks are also lacking.
It is true that a diet high in meat and dairy – and low in fruit and vegetables – can acidify your urine (but not your blood). But there's no evidence that acidic urine causes bone loss or osteoporosis. And there's no proof that dairy products are detrimental to bone health. In fact, for older adults getting too little protein – be it from dairy, meat, poultry, fish or eggs – is a bigger problem for bone health than eating too much animal protein. (Acidic urine is, however, linked to certain types of kidney stones.)
Is the alkaline diet healthy? There's no question a regular intake of alkaline foods is good for you. Eating more fruit and vegetables increases your intake of potassium, a mineral linked to protection from high blood pressure and stroke. A steady intake of magnesium-rich beans (e.g. kidney beans, black beans, chickpeas) and lentils helps guard against heart disease, Type 2 diabetes and prostate cancer. Avoiding foods packed with sodium and refined sugar is beneficial too.
But depending on which version of the alkaline diet you follow, you could be lacking protein and key vitamins and minerals. Strict alkaline diets eliminate all meat, poultry, fish, eggs, dairy and grains, which can lead to nutrient deficiencies.
Other plans advocate a more balanced approach of eating 60 per cent alkaline-forming foods and 40 per cent acid-forming foods. Be forewarned that many websites offering information on the diet sell e-courses, books and supplements to help you get started on the plan.
My advice: Stick to a diet that is easy to follow, nutritious, safe and backed by plenty of scientific evidence. Your best bets for overall health: the Mediterranean and DASH diets.
Leslie Beck, a registered dietitian, is based at the Medisys clinic in Toronto. She can be seen every Thursday at noon on CTV News Channel's Direct (lesliebeck.com).