One argument for alkaline pH food leans on history. Our distant ancestors, the story goes, ate a diet that left the body with a base surplus, and modern eating flipped that to an acid surplus. Two groups of researchers put numbers on that story. What they found is more mixed than the slogan, and it says something useful about where a fruit like dates sits on the plate.
The 2002 estimate
Anthony Sebastian and colleagues at the University of California, San Francisco, estimated the net acid load of the diet, which they call net endogenous acid production (NEAP), for 159 reconstructed preagricultural diets (PubMed 12450898). The mean came out at −88 mEq a day, with a wide spread of ±82. Of those diets, 87% were net base-producing.
The same model put the average American diet, as recorded in the third National Health and Nutrition Examination Survey, at +48 mEq a day. The authors say that figure was within a few percentage points of published measured values, so the model was not simply built to produce negative numbers.
Their explanation for the change is specific. Plant foods that yield a lot of bicarbonate were displaced by cereal grains and by energy-dense, nutrient-poor foods. In their words, neither of those is net base-producing.
The 2010 recount
Eight years later, Ströhle, Hahn and Sebastian, working from Leibniz University of Hannover, ran the sums again for 229 hunter-gatherer societies described in historical ethnographic records (PubMed 20042527). They used each group's recorded ratio of plant to animal food and tested four assumptions for how fat the hunted animals were, from 3% to 20% fat.
The result depended heavily on how much of the diet came from animals. With the leanest-meat model, as the plant-to-animal ratio moved from 85:15 to 5:95, NEAP climbed from −178 to +181 mEq a day. Under the two middle models, about half of the 229 diets were net acid-producing. Under the fattiest-meat model, 40% were.
A second paper by the same team that year added geography (PubMed 20702605). Diets tended to be net acid-producing above about 40° latitude and net base-producing below it in three of the four models. Groups living in tundra and northern conifer forest, temperate grassland and tropical rainforest came out net acid-producing. The authors still concluded that the data support a mainly base-producing diet for the East African ancestors of Homo sapiens.
What that means for the word "required"
So the ancestral case is real, but it is not universal. Roughly half of the historically studied hunter-gatherer diets in the 2010 count were net acid-producing, which makes it hard to say a base-producing diet is something every human population has lived on.
It also helps to be clear about what is being measured. These papers estimate the acid load a diet hands to the body to deal with. Their abstracts report that estimate, not blood pH. Gerry Schwalfenberg's 2012 review (PubMed 22013455) notes that human life requires a tightly controlled serum pH of about 7.4, within 7.35 to 7.45, while urine may vary from acid to alkaline depending on what the body needs to balance. Remer and Manz found that net acid excretion tracked urine pH closely (r = .83; PubMed 7797810). Food shifts the urine. The blood figure is held in a narrow band.
Grain against fruit, 100g each
Sebastian's point about grains can be checked on an ordinary plate. Scialla and Anderson's 2013 review (PubMed 23439373) lists cheese, meat, eggs and grains among the common foods that impart a dietary acid load, while fruits and vegetables provide alkali. It also quotes the potential renal acid load (PRAL) equation adapted from Remer: 0.49 × protein + 0.037 × phosphorus − 0.021 × potassium − 0.026 × magnesium − 0.013 × calcium.
Put USDA FoodData Central figures for 100g of each food through that equation:
- Cooked long-grain white rice (FDC 168878: 2.69g protein, 43mg P, 35mg K, 12mg Mg, 10mg Ca) comes out at about +1.7.
- Deglet Noor dates (FDC 171726: 2.45g protein, 62mg P, 656mg K, 43mg Mg, 39mg Ca) come out at about −11.9.
- Medjool dates (FDC 168191: 1.81g protein, 62mg P, 696mg K, 54mg Mg, 64mg Ca) come out at about −13.7.
The rice is only mildly on the acid side. The dates are well on the base side, mostly because of their potassium. Remer and Manz put the average for fruit, fruit juice and vegetables at roughly −3 per 100g, so dates score several times lower than that average. Weight for weight is not portion for portion, though. FDC lists the dates at 282 and 277 kcal per 100g, against 130 kcal for the cooked rice, so 100g of dates is a lot more food energy than 100g of rice.
That is the fair version of the ancestral argument as it applies to dates. They will not change your blood pH. On these numbers, 30g of Deglet Noor (about −3.6) more than offsets the +1.7 of 100g of cooked rice, so adding dates to a rice meal tips its acid load toward the base side.
Mazafati and the dates in this article
The figures above use the USDA records for Deglet Noor and Medjool. Mazafati, the date this site is named after, comes from Bam in Kerman province, Iran. It is dark, very soft and high in moisture, needs refrigeration, and is cold-stored so it can be sold all year.
The about page says the site serves retail and wholesale buyers (runcit & borong), with delivery across Malaysia and customer service on WhatsApp. For a quote, the WhatsApp number is on the contact page, and other date articles are listed on the blog. A link kept from the earlier version of this post points to Kurma Mazafati Malaysia.
The video below is from the YouTube channel AbuAyyash Farms, titled as a look at Medjool date farming and a date processing factory.
This article is general information about diet research, not personal advice. If you have a health condition or take regular medication, speak to your doctor before making big changes to what you eat.