18 replies to this topic

[Skötkonung]

I was just curious if anyone had tried a diet that involved balancing the PRAL (potential renal acid load) of foods. The objective of such a diet would be to average a neutral value of 0.

From FoodFitHealth.com:
"If homeostatic mechanisms cannot control plummeting acidity, as is the case in ketoacidosis, which can occur in diabetics with poorly controlled blood sugar, death can result. This is called ‘metabolic acidosis’. Metabolic alkalosis can also occur. Both are life threatening if not quickly corrected. It is a complex process with calcium, magnesium, phosphorus and potassium and sodium and perhaps vitamins K and D involved in regulatory control, particularly in relation to bone which supplies calcium as part of the buffering mechanism."

Common PRAL scores of foods:
 Remer_and_Manz_Acid_Base.pdf   796.83KB   141 downloads

[Skötkonung]

PRAL scores of common foods:
(Negative numbers indicate base or alkaline-producing foods and positive numbers are acid-producing foods)

Beverages
Beer, draft -0.2
Beer, pale 0.9
Beer, stout bottled -0.1
Coca-cola 0.4
Cocoa, made with semi-skimmed milk -0.4
Coffee, infusion 5 minutes -1.4
Mineral water (Apollinaris) -1.8
Mineral water (Volvic) -0.1
Red wine -2.4
Tea, Indian infusion -0.3
White wine, dry -1.2

Fats and Oils
Butter 0.6
Margarine -0.5
Olive oil 0.0
Sunflower seed oil 0.0

Fish
Cod fillets 7.1
Haddock 6.8
Herring 7.0
Trout, brown steamed 10.8

Fruits and Fruit Juices
Apple Juice, unfiltered -2.2
Apples, 15 varieties flesh & skin, average -2.2
Apricots -4.8
Bananas -5.5
Black currants -6.5
Cherries -3.6
Grape juice, unsweetened -1.0
Kiwi fruit -4.1
Lemon juice -2.5
Orange juice, unsweetened -2.9
Oranges -2.7
Peaches -2.4
Pears, 3 varieties flesh and skin, average -2.9
Pineapple -2.7
Raisins -21.0
Strawberries -2.2
Watermelon -1.9

Nuts
Hazlenuts -2.8
Walnuts 6.8

Grain Products
Bread, rye flour mixed 4.0
Bread, rye flour 4.1
Bread, wheat flour mixed 3.8
Bread, wheat flour whole meal 1.8
Bread, white bread 3.7
Cornflakes 6.0
Crispbread, rye 3.3
Noodles, egg 6.4
Oat flakes, rolled oats 10.7
Rice, brown 12.5
Rice, white, easy cook 4.6
Rice, white, easy cook, boiled 1.7
Rye flour, whole 5.9
Spaghetti, white 6.5
Spaghetti, whole meal 7.3
Wheat flour, white plain 6.9
Wheat flour, whole meal 8.2

Legumes
Beans, green/French beans -3.1
Lentils, green and brown, whole, dried 3.5
Peas 1.2
Peanuts, plain 8.3

Meat and Meat Products
Beef, lean only 7.8
Chicken, meat only 8.7
Corned beef, canned 13.2
Frankfurters 6.7
Liver sausage 10.6
Luncheon meat, canned 10.2
Pork, lean only 7.9
Rump steak, lean and fat 8.8
Salami 11.8
Turkey, meat only 9.9
Veal, fillet 9.0

Milk, Dairy Products
Buttermilk 0.5 Camembert cheese 14.6
Cheddar cheese, reduced fat 26.4
Cheese, Gouda 18.6
Cottage Cheese, Plain 8.7
Creams, fresh, sour 1.2
Fresh Cheese (Quark) 11.1
Full fat, soft cheese 4.3
Hard cheese, average 4 types 19.2
Ice Cream, dairy, vanilla 0.6
Whole milk, evaporated 1.1
Whole milk, pasteurized 0.7
Parmesan cheese 34.2
Processed cheese, plain 28.7
Yogurt, whole milk, fruit 1.2
Yogurt, whole milk, plain 1.5

Eggs
Eggs, chicken, whole 8.2
Egg white 1.1
Egg yolk 23.4

Sugar, preserves and sweets
Chocolates, milk 2.4
Honey -0.3
Madeira cake 3.7
Marmalade -1.5
Sugar, white -0.1

Vegetables
Asparagus -0.4
Broccoli, green -1.2
Carrots, young -4.9
Cauliflower -4.0
Celery -5.2
Chicory -2.0
Cucumber -0.8
Eggplant -3.4
Leeks -1.8
Lettuce, average 4 varieties -2.5
Lettuce, iceberg -1.6
Mushrooms, common -1.4
Onions -1.5
Peppers, green -1.4
Potatoes, old -4.0
Radish, red -3.7
Spinach -14.0
Tomato juice -2.8
Tomatoes -3.1
Zucchini -4.6

[Skötkonung]

I think the interesting implication here is that a high protein diet (protein from animal product, not plants like soya and hemp) will inevitably lead to a degradation of bodily systems from a prolonged mild acidosis. To consume a 20-30% protein diet from meat would require a large volume of fruit and vegetables to offset its acidic PRAL value. I think this puts the nail in the coffin for the ultra low carb diet and longevity.

[JLL]

What evidence do we have that a prolonged mild acidosis leads to a degradation of bodily systems?

[Sillewater]

I would like to see some studies as well. My friends talk about the acid/base balance diet and I have been wondering if the acidosis is a problem. Or does our bodies have the capacity to handle the acidosis (homeostasis).

[HaloTeK]

Skotkonung, are you familiar with Lex from the raw paleo forum? Im not saying his diet is optimal for longevity, but his urine is acidic and around ph5 and he doesnt seem to be suffering. His recent bone scan was good. Care to comment?

I think our body can manage ph throughout our body through respiration-- I feel food matters alot less.

We know low protein intake- especially low methio is good for longevity, less is known about optimal carb and fat intake

[Skötkonung]

To be honest, I haven't specifically gone looking for studies on the effects of a prolonged mild acidosis. However, some of the texts I have read seem to indicate that an imbalanced diet high in acidic-producing foods such as animal protein, sugar, caffeine, grains, and processed foods puts pressure on the body's regulating systems to maintain pH neutrality. The extra buffering required can deplete the body of alkaline minerals such as sodium, potassium, magnesium, and calcium, making the person prone to chronic and degenerative disease. Minerals are borrowed from vital organs and bones to buffer (neutralize) the acid and safely remove it from the body. Because of this strain, the body can suffer severe and prolonged damage--a condition that may go undetected for years. This is why we develop osteoporosis as we age.

Susan Brown, Ph.D., who heads the nonprofit Osteoporosis Education Project in East Syracuse, N.Y., frames the acid-alkaline issue as one of mineral adequacy and depletion: "It's a little like over-farming and depleting mineral levels in soil,".... "If we eat foods that create an acidic pH in the body, we will deplete our bones of minerals."

That is why long lived cultures who eat exclusively low-carb tend to have high incidences of osteoporosis and osteoarthritis: Health survey to screen Inuit for osteoporosis
"We did a study with Greenlandic doctors, and basically we found that compared to a group of 5,000 women in Quebec City, the frequency of osteoporosis was 19 per cent compared to 7 per cent," said Dr. Eric Dewailly of the National Institute of Public Health in Quebec .

"It was like two-and-a-half times higher, so it's very high. That was not known."

Although there has been some thinking that pollution could be causing these diseases. However, is this is the case, why does America with its extremely high calcium intake still have very high rates of osteoporosis?


Since both osteoporosis and osteoarthritis tend onset sometime in the early to mid 60s, it is impossible to tell whether paleolithic humans suffered from these diseases given that the oldest specimens are usually incomplete and are from individuals younger than 50. However, cultures in Canada, Alaska, and Greenland seem to depict extreme examples of what happens when living a prolonged low-carb lifestyle.

My take on the issue is Helena Kloosterman. She says:
Our ancestors ate meat and lots of vegetables, but no grains. Their general diet was alkaline and they were generally healthy. People in rural China and other developing countries eat whole grains and lots of vegetables, but no meat. Their diet is alkaline, and they are generally healthy. Most people in industrialized countries eat meat and grains and almost no fruit and vegetables at all. They are not very healthy.

Dr Eades seems to skirt around this issue in his posts, but when confronted he has said that it takes very little vegetables to counter the acidic qualities of meat. Having personally done the math, I disagree. Since meat and grains are much more acidic than vegetables are alkaline and because meat has much less volume per given weight than vegetables, you would need to consume at least 2 part vegetables and fruits for every 1 part meat to maintain a alkaline diet.

This seems to be an affront to the typical paleodiet of Dr Eades and Mark Sisson that prescribes a high fat, medium protein, low carb lifestlye. If anything, this more or less reinforces Loren Cordain's view of a paleodiet that is medium in protein and very high in fresh vegetables and fruits. I'm not saying the paleo diet is wrong, I just think that in terms of longevity some alteration may be needed to prevent the age related decline of our skeletal systems.

[Skötkonung]

Loren Cordain discusses PRAL scores of foods:
http://www.thepaleod...ools/acid.shtml

</h3>

<h3>Acid-Base Balance and Your Health
In the U.S. calcium intake is one of the highest in the world, yet paradoxically we also have one of the highest rates of bone demineralization (osteoporosis). Bone mineral content is dependent not just upon calcium intake but upon net calcium balance (calcium intake minus calcium excretion). Most nutritionists focus upon the calcium intake side of the calcium balance equation, however few realize that the calcium excretion side of the equation is just as important.

Bone health is substantially dependent on dietary acid/base balance. All foods upon digestion ultimately must report to the kidney as either acid or base. When the diet yields a net acid load (such as low-carb fad diets that restrict consumption of fruits and vegetables), the acid must be buffered by the alkaline stores of base in the body. Calcium salts in the bones represent the largest store of alkaline base in the body and are depleted and eliminated in the urine when the diet produces a net acid load. The highest acid-producing foods are hard cheeses, cereal grains, salted foods, meats, and legumes, whereas the only alkaline, base-producing foods are fruits and vegetables. Because the average American diet is overloaded with grains, cheeses, salted processed foods, and fatty meats at the expense of fruits and vegetables, it produces a net acid load and promotes bone demineralization. By replacing hard cheeses, cereal grains, and processed foods with plenty of green vegetables and fruits, the body comes back into acid/base balance which brings us also back into calcium balance. The goal is to avoid a net acid load on your kidneys.

The Paleo Diet recommends an appropriate balance of acidic and basic (alkaline) foods (i.e., lean meats, fish and seafood, fruits, and vegetables) and will not cause osteoporosis in otherwise healthy individuals. Indeed, The Paleo Diet promotes bone health.

In addition to promoting bone demineralization, a net acid-producing diet also contributes to the following maladies and illnesses: calcium kidney stones, age-related muscle wasting, hypertension, stroke, asthma and exercise-induced asthma.

Edited by Skotkonung, 04 September 2009 - 10:53 PM.

[Sillewater]

Thanks for providing the information on the Inuit. Interesting stuff. And the reasoning makes sense (though i would like to see the results through a study, the Inuits are a pretty good example).

What I'm curious about is why fruits are alkaline. If sugary foods are acidic what makes fruit alkaline?

Also here's another list of a lot more foods with their PRAL scores:

http://www.bitterpoi.../files/pral.txt

[kismet]

Acidosis. Bad for the bones, but the reverse of that argument would be that it'd protect from pathologic calcification. Although, the classical view is/was that it is also bad for the vasculature (endothelial dysfunction?) You gotta have some trade-offs. I'd love to see all-cause mortality and CVD data from a big, prospective cohort, otherwise it's difficult to meaningfully answer the question.

Edited by kismet, 12 September 2009 - 09:24 PM.

[Sillewater]

Thanks kismet, forgot about the endothelial dysfunction. Hmm, more complicated then I thought, as always.

[Sillewater]

Paleolithic diet, sweet potato eaters, and potential renal acid load.

Remer T, Manz F.
PMID: 14522740 [PubMed - indexed for MEDLINE]

Taken together, we also conclude that the average Paleolithic diet principally led to net base production (yielding a negative PRAL), but was possibly less alkaline than suggested by Sebastian et al. One of several uncertainties in this respect is obviously the intake of those OAs not metabolically combusted but renally excreted, eg, phenolic acid, which is excreted in the form of hippuric acid. Reasons for the historical shift from negative to positive PRAL are not only the displacement of alkali-rich plant foods in the ancestral diet by cereal grains and nutrient-poor foods in the temporary diet but also the modern processing and preparation of foods, which lead to considerable losses of base-forming nutrients such as potassium and magnesium.

Found this letter discussing PRAL and NEAP, stating that paleolithic diets were probably negative in the PRAL score. They gave the example of a Papuan tribe in New Guinea who were low protein vegetarian and have a higher acidic load. They say its because organic acids are usually left out of the calculations and when included make a big difference.

For those of us who have higher protein intakes, maybe we could just drink some club soda. The PRAL score is negative.

[yoyo]

SCIENCEFAIL

Dietary protein and calcium interact to influence calcium retention: a controlled feeding study1,2,3,4
Janet R Hunt, LuAnn K Johnson and ZK Fariba Roughead

Background: The effect of meat protein on calcium retention at different calcium intakes is unresolved.

Objective: The objective was to test the effect of dietary protein on calcium retention at low and high intakes of calcium.

Design: In a randomized controlled feeding study with a 2 x 2 factorial crossover design, healthy postmenopausal women (n = 27) consumed either {approx}675 or {approx}1510 mg Ca/d, with both low and high protein (providing 10% and 20% energy) for 7 wk each, separated by a 3-wk washout period. After 3 wk, the entire diet was extrinsically labeled with 47Ca, and isotope retention was monitored by whole-body scintillation counting. Clinical markers of calcium and bone metabolism were measured.

Results: High compared with low dietary protein significantly increased calcium retention from the low-calcium (29.5% compared with 26.0% absorbed) but not the high-calcium diet (18% absorbed). For the low-calcium diet, this effect nearly balanced a protein-related 0.5-mmol/d greater urinary calcium excretion. Protein-related calciuretic effects were independent of dietary calcium. Testing at 1, 2, 3, 5, and 7 wk showed no long-term adaptation in urinary acidity or urinary calcium excretion. High compared with low dietary protein decreased urinary deoxypyridinoline and increased serum insulin-like growth factor I without affecting parathyroid hormone, osteocalcin, bone-specific alkaline phosphatase, or tartrate-resistant acid phosphatase.

Conclusions: In healthy postmenopausal women, a moderate increase in dietary protein, from 10% to 20% of energy, slightly improved calcium absorption from a low-calcium diet, nearly compensating for a slight increase in urinary calcium excretion. Under practical dietary conditions, increased dietary protein from animal sources was not detrimental to calcium balance or short-term indicators of bone health.

Phosphate decreases urine calcium and increases calcium balance: A meta-analysis of the osteoporosis acid-ash diet hypothesis

Tanis R Fenton email, Andrew W Lyon email, Michael Eliasziw email, Suzanne C Tough email and David A Hanley email

Nutrition Journal 2009, 8:41doi:10.1186/1475-2891-8-41
Published: 15 September 2009
Abstract (provisional)

Background

The acid-ash hypothesis posits that increased excretion of "acidic" ions derived from the diet, such as phosphate, contributes to net acidic ion excretion, urine calcium excretion, demineralization of bone, and osteoporosis. The public is advised by various media to follow an alkaline diet to lower their acidic ion intakes. The objectives of this meta-analysis were to quantify the contribution of phosphate to bone loss in healthy adult subjects; specifically, a) to assess the effect of supplemental dietary phosphate on urine calcium, calcium balance, and markers of bone metabolism; and to assess whether these affects are altered by the b) level of calcium intake, c) the degree of protonation of the phosphate.
Methods

Literature was identified through computerized searches regarding phosphate with surrogate and/or direct markers of osteoporosis. Studies were assessed for methodological quality. Multiple linear regression analyses, weighted for sample size, were used to combine the study results. Tests of interaction included stratification by calcium intake and degree of protonation of the phosphate supplement.
Results

Twelve studies including 30 intervention arms manipulated 269 subjects' phosphate intakes. Three studies reported net acid excretion. All of the meta-analyses demonstrated significant decreases in urine calcium excretion in response to phosphate supplements whether the calcium intake was high or low, regardless of the degree of protonation of the phosphate supplement. None of the meta-analyses revealed lower calcium balance in response to increased phosphate intakes, whether the calcium intake was high or low, or the composition of the phosphate supplement.
Conclusions

All of the findings from this meta-analysis were contrary to the acid ash hypothesis. Higher phosphate intakes were associated with decreased urine calcium and increased calcium retention. This meta-analysis did not find evidence that phosphate intake contributes to demineralization of bone or to bone calcium excretion in the urine. Dietary advice that dairy products, meats, and grains are detrimental to bone health due to "acidic" phosphate content needs reassessment. There is no evidence that higher phosphate intakes are detrimental to bone health.

[Skötkonung]

SCIENCEFAIL

Epidemiological evidence fail. I'm guessing you never bothered to look at population studies in regards to osteoporosis?

What does this graph indicate: http://www.natofemin...lcomparison.gif

Higher intake of animal products, grains, and dairy are linked to higher rates of osteoporosis. Studies going back almost a century describe the bone loss that can occur in people following a predominately meat diet. A diet high in meat alone creates a mild metabolic acidosis in the human body. This metabolic acidosis or excess acid created by the metabolism of meat has to be buffered or neutralized, which the body does by leaching calcium from the body's storehouse of calcium, the bones. On a day-to-day basis (which EXCLUDES the short term studies you are referencing) the amount of calcium lost from the bones in this way is insignificant, but over a decades-long period of time can result in osteoporosis.

Even low-carb people, such as Dr Eades, don't rebut this fact.

Edited by Skotkonung, 28 September 2009 - 08:08 PM.

[kismet]

Shotkung, what's the biggest contributor to PRAL values, is it phosphate or something else? I think the phosphate meta-analysis is correct. Dietary phosphate raises blood phosphate somewhat, which contributes to mineralisation likely via a physiochemical process (Ca x Pi!) or direct stimulation of osteogenesis. There is quite some evidence suggesting that a positive phosphate balance improves bone mineralisation. Whether this is somehow outweighed by high PRAL values of phosphate rich foods is another question. The influence of (blood) pH on mineralisation is also a fact. These mechanisms may possibly counteract eachother in the case of phosphate intake (depending on intake levels).

High phosphate & low pH blood levels would be optimal for bone mineralisation. But high phosphate levels are strongly linked to CVD and the influence of pH levels on all-cause mortality is likely unresolved (I've already explained that it could easily contribte to CVD via pathological calcification -- we need actual, prospective, well-sized trials to answer this question).

Edited by kismet, 29 September 2009 - 11:48 AM.

[yoyo]

SCIENCEFAIL

Epidemiological evidence fail. I'm guessing you never bothered to look at population studies in regards to osteoporosis?

What does this graph indicate: http://www.natofemin...lcomparison.gif

Higher intake of animal products, grains, and dairy are linked to higher rates of osteoporosis. Studies going back almost a century describe the bone loss that can occur in people following a predominately meat diet. A diet high in meat alone creates a mild metabolic acidosis in the human body. This metabolic acidosis or excess acid created by the metabolism of meat has to be buffered or neutralized, which the body does by leaching calcium from the body's storehouse of calcium, the bones. On a day-to-day basis (which EXCLUDES the short term studies you are referencing) the amount of calcium lost from the bones in this way is insignificant, but over a decades-long period of time can result in osteoporosis.

Even low-carb people, such as Dr Eades, don't rebut this fact.

the japanese diet is low grain? the people worship rice. so i guess your theory is danish (not english) milk consumption is leeching bones.

[Skötkonung]

the japanese diet is low grain? the people worship rice. so i guess your theory is danish (not english) milk consumption is leeching bones.

Well according to the publication, World-wide projections for hip fracture in Osteoporosis International, 50% of all hip fractures related to osteoporosis will occur in Asia by 2050. Furthermore, osteoporosis is greatly under-diagnosed and under-treated in Asia, even in the most high risk patients who have already fractured. The problem is particularly acute in rural areas. In the most populous countries like China and India, the majority of the population lives in rural areas (60% in China), where hip fractures are often treated conservatively at home instead of by surgical treatment in hospitals. The prevalence of osteporosis in the Japanese female population aged 50-79 years has been estimated to be about 35% at the spine and 9.5% at the hip. New hip fractures increased a dramatic 1.7-fold in the 10 years from 1987 to 1997. The total number of hip fractures in Japan is forecast to be 153,000 per year in 2010 and 238,000 in 2030.

The bottom line is that osteoporosis is a big problem in Asian countries because of their high grain consumption. The asian diet is no miracle diet for preserving the bones.

I pulled these stats from the Japanese Osteoporosis Foundation. More stats.

BTW, perhaps you've not been to Europe, but we have different foods and cultures in each country. And milk, according to the charts above, is not very acidic.

Edited by Skotkonung, 03 October 2009 - 02:34 AM.

[tunt01]

PRAL scores of common foods:
(Negative numbers indicate base or alkaline-producing foods and positive numbers are acid-producing foods)

Beverages
Coffee, infusion 5 minutes -1.4

I thought coffee was considered to be extremely acidic, not alkaline-inducing.

[Skötkonung]

PRAL scores of common foods:
(Negative numbers indicate base or alkaline-producing foods and positive numbers are acid-producing foods)

Beverages
Coffee, infusion 5 minutes -1.4

I thought coffee was considered to be extremely acidic, not alkaline-inducing.

Well PRAL values are the PH as it passes through the kidneys, not at point of ingestion.