Acid-Base Balance

January 5, 2012 in Categories: by

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A paleolithic diet puts strong emphasis on consuming plant matter (which is typically done in a carbohydrate conscious way).  Obviously, vegetables, fruits, nuts and seeds are an essential source of vitamins and minerals.  But there is another, equally important reason to consume these foods:  acid-base balance.  What does this mean?  Well, I’m sure you’re thinking about what acids you know (vinegar, lemon juice, battery acid) and what bases you know (baking soda, soap, bleach).  Yes, we are talking about the same thing, but not how acidic or alkaline foods are when you eat them.  Rather, the important part here is whether the digested compounds from those foods are acidic or alkaline (which means the same as basic) when they are filtered by your kidneys.

The kidneys are a pretty wonderful pair of organs.  Of course, they are responsible for filtering our blood, adjusting the level of essential chemicals in the body, and eliminating unnecessary elements and wastes.  But, they are also responsible for regulating the salinity of the blood, for producing hormones that regulate blood pressure, for producing hormones that stimulate red blood cell production, and for regulating the body’s pH by adjusting the body’s acid-base balance.

All food, once digested, contains compounds that must be filtered by the kidneys.  These compounds can be acidic (meaning they have hydrogen ions to donate) or alkaline/basic (meaning they are short hydrogen ions and would like to gobble some up from somewhere) or neutral (just the right number of hydrogen ions).  If the blood is too acidic, meaning that there is an excess of hydrogen ions, the kidney moves these ions to the urine.  If your diet is deficient in alkaline foods, your kidneys use calcium from your bones to process the extra hydrogen ions.  The body runs most effectively in a slightly alkaline state.  The normal pH of blood is 7.4 (slightly basic) and this is necessary for the health of every cell in your body.

So what foods are acidic and what foods are basic?  Well first, many of the foods we already avoid on a paleolithic diet are acidic.  Grains, legumes, dairy products, modern vegetable oils and salt are all moderately to highly acidic at the level of the kidneys.  If these foods form any part of your diet, it is important to balance these acidic foods with lots of alkaline foods.  Alkaline foods are basically all fruits and vegetables.  Eggs are very slightly alkaline (you could just consider them neutral).   Some nuts and seeds are alkaline while others (especially those higher in omega-6 fats) are acidic. Many people believe that in order to balance the acidic load of meat, poultry, fish and shellfish in a paleo diet, that we need to consume large amounts of alkaline vegetables.  However, recent research shows that high-protein, low-carbohydrate diets do not cause bone demineralization. This may be because meat, poultry, shellfish and fish actually contribute enough dietary calcium, magnesium and phosphorous as well as essential amino acids to your diet to protect your bones.   What does this mean for acid-base balance?  Actually, it’s still important.  No one has yet looked at the effect of a pure protein and fat diet on bone health.  Also, meat quality likely plays a key role here since high omega-6 content seems to contribute to the acid load on your kidneys. Consuming vegetables is still an important way to protect your bones  and your kidneys, while also providing many key vitamins and minerals unavailable in meat.  And it is still true that the more alkalizing foods you consume, the better.   If you are being careful not to consume too much fruit due to the fructose content, then you need to make sure you are eating lots of vegetables.  I eat vegetables at every meal.  It may seem strange at first (especially eating vegetables at breakfast), but shifting toward a high vegetable intake will make an enormous difference to your long-term health.

Comments

I have read about kidney biochemistry and function in textbooks, so I am confident that I am presenting accurate information here.  But there is alot of conflicting information out there.  There are maybe three points that I should have mentioned.  First, the lungs are also important in regulating acid-base balance in the body.  The job that the kidneys and lungs do is a little different so they really work together.  Second, food is not the only source of hydrogen or carbonate ions that will affect blood pH and require the kidneys to do some work. But food is one thing that we can control.  Third, eating a diet rich in acidic foods (like an all-meat diet or the Standard American Diet) strains the kidneys but this doesn’t necessarily show up as a major health issue right away.  The kidney are very resilient and it can take decades for the strain to manifest as a condition (kinda like how smoking a couple of cigarettes a day can take decades to show the damage). In the case of acid-base balance, the two conditions that you might eventually see are kidney stones and osteoporosis. If you want more information, Professor Lorain Cordain’s dedicates a good section of his book The Paleo Diet to this topic (there should be a link on the right side of my blog).

I’ve been following your blog for a month or so and am such a fan. Not only are you smart and know your stuff, but you’re a good teacher, unpretentious, and share your own experience. I’ve also followed Chris Kresser for a while now and his 2 part write up on this topic threw me just when I thought I had it all figured. He has quite a compelling argument about what we ingest, having little impact on systemic pH. Can you help me understand how it all ties up?

It does have very little impact because the body corrects pH very quickly (it does this because our tolerance for pH is VERY narrow, and even a difference between 7.4 and 7.3 can be very dangerous). It’s not that our bodies become acidic or basic as a result of what we eat. Food definitely can cause an acid load or a base load, but the kidneys get that fixed almost as quickly as it happens. Instead, it’s about how the kidneys are able to fix the pH and how hard they have to work to do so. I was at a talk this weekend at AHS by an MD who was discussed in part of her talk the link between exactly this (mainly not enough alkaline foods, i.e., not enough vegetables) and bone health. It’s quite a complex system, and I definitely this this (very old) post of mine is an oversimplification and something I should discuss with more nuanced detail in a future post.

Thank you for your reply Sarah, as busy as you are. I just bought your book today (amazon for kindle). Am looking forward to reading it. I send many of your articles as PDF’s to my friends who are trying to get healthy. Keep up the wonderful work!

We indulge ourselves in sweets, fatty foods, alcohol, sodas and a host of other highly refined, highly acid producing substances that tear down our natural defenses and render our bodies incapable of maintaining an optimum balance of health and energy. Alkaline Foods

What about constipation? It seems like if I eat anything other than meat I suffer from it. have you heard of fiber menace….his premise is that the fiber in fruits and veggies causes it.

I get constipated from grain-based fibers – metamucil, fiber supplements, flaxseed, even miralax. Kale smoothies are great, though. So is magnesium. I take calcium citrate and magnesium citrate powder in a 2:1 ratio. But relatively more Mg if things start getting sluggish.

I’m a new reader of your blog. Due to digestion issues with dairy and grains I have been reading everything I can for the last few weeks. I’ve never been a meat eater, in fact, I’ve always believed that meat-free is healthier. However, your very educational blog posts have me interested. Can I ask your thoughts about meat causing an acidic environment in the body? I’ve spent years reading about the acidic body/cancer connection. I’ve always read that meat, dairy, and sugar are acid forming, and that in turn promotes cancer growth. I would love to hear your thoughts on this, as I am so nervous about adding meat into my diet. My dermatologist told me I have a high likelihood of melanoma due to the amount of moles I have, so I get paranoid about my diet and what I put in and on my body. Thank you.

The high meat diets causing an acid load on the kidneys has been debunked in the scientific literature. It is important to note that studies showing a correlation between meat consumption and cancer have that correlation evaporate as soon as vegetable intake is accounted for, meaning it’s not high meat diets that increase risk but rather diets that are simultaneously high in mean and low in vegetables. It appears as that chlorophyll itself alters the metabolism of the iron molecule heme found abundantly in red meat and prevent the production of carcinogenic byproducts. It’s my recommendation to eat meat and seafood (and including organ meat) as well as large portions of a variety of vegetables.

Hi, interesting blog! I’ve been trying to live healthier, mostly by trying to avoid meat, eggs, and dairy, at least during the week, but if I actually manage this for a few days I feel drained, hungry and tired! Because of my osteoporosis I thought I’m supposed to avoid too much protein, could you reference the study mentioned above, (HPLC diets don’t cause bone demineralisation)?

I’m no longer eating any grain, dairy, or sugar in my diet. Not even honey or maple syrup or stuff like that, since those alternatives make me feel tired. I use dates for sweetening the occasional goodie actually, but anyways the acid and base balance is easy for me, i just listen to what my body craves. Some days ill crave more meat or veges than others. That’s totally okay though, since im stocked up on all of those, especially kale and collard greens. Boy do i love those! I’m trying to maintain my weight though and crave a lot of fruit, i just had banana pancakes and strawberries this morning. My mother on the other hand wants to lose weight, would that mean cutting down on the fruits shes having? I dont know, anyway I’m feeling great on this diet so far, no longer getting bloated from grains! Hated that feeling…Cant seem to convince my father that grains and dairy aren’t needed though, its a pain to convince him of anything. He says i have no proof but isnt ME feeling better from not having it proof enough? Yeesh…

Right now, I have about 17 tabs open in my browser, all associated with your blog! I’ve probably read twice that many already. One of the things I read at another site about the acid/base balance suggested juicing a lemon into a glass of water each morning to help make your body more alkaline; and that this helps remove deposits in the joints – important to me, as I have osteoarthritis. I’ve been drinking lemon juice in water for about three months, and have come to really enjoy doing it; but I’m still a bit baffled as to the mechanism by which drinking an acidic fluid – lemon juice – helps make the body more alkaline. Can you help with any insight? Thank you; and rest assured I will be reading many more posts on your site!

Well, I’m not sure that lemon juice would actually accomplish this, but the idea is actually to alkaline chemicals to the kidneys for chemical reactions there. This would be a subset of the compounds in lemon juice. Citrus is high in betaine, which supports the methylation cycle, which is as close as I can think of as to why lemon juice would be beneficial in acid-base balance.

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