This piece on alkaline food starts in the ground, not in the body. pH matters to a date palm long before anyone eats the fruit, and one of the reviews below ends its advice on alkaline eating by pointing back at the soil. So the number is followed here from field to plate, and the title's question is answered at the end with what the research supports.
pH in the soil a crop grows in
Gerry Schwalfenberg's 2012 review of the alkaline diet turns to soil in its first section. It says the ideal soil pH for the best overall availability of essential nutrients is between 6 and 7. Below 6, soils may have reduced calcium and magnesium. Above 7, iron, manganese, copper and zinc may become chemically unavailable. Adding dolomite and manure are ways of raising the pH of an acid soil (PubMed 22013455).
Date farms deal with the other end of that scale. The FAO's date palm cultivation handbook says the palm can grow and produce in many types of soil in hot arid and semi-arid regions, from very sandy to heavy clay. It also says saline and alkaline soils are common in date plantations. In its terms an alkaline soil has a pH higher than 8.5, carries harmful amounts of alkalis such as sodium hydroxide, and is usually difficult to correct, with low production from a low content of calcium and nitrogen.
Why date farms fight salt
The handbook explains where much of the salt comes from. Where date palms grow with little rain, great heat and much evaporation, irrigation or flood water evaporates quickly and leaves its salts on the surface. A white layer on the ground is the sign of a saline soil.
Growers have a few tools. Saline soils need leaching to drain the excess salts. In alkaline and saline-alkaline soils, sodium can be replaced by applying gypsum or an acidifying agent like sulphur. Organic matter helps as well, since a higher humus content limits the harmful effects of alkalinity and improves the leaching of salts. Winter rainfall, the climate chapter adds, benefits plantation soils by washing out deposited surface salt.
The same chapter makes a point that is easy to miss. The date palm is not a true halophyte, the FAO says, despite its healthy growth in exceedingly salty places, because it grows better when the soil and water are sweet. Coping with salty ground is not the same as preferring it.
pH in the body is a different story
Inside a person, pH is not one number. Schwalfenberg lists the stomach at pH 1.35 to 3.5 to aid digestion, and the skin at 4 to 6.5 as an acid barrier. Blood is held in a tight, slightly alkaline range of 7.35 to 7.45. The body keeps it there mainly through the kidneys and the lungs, which he calls the main compensatory mechanisms. Urine is the part that moves: it can range from acid to alkaline depending on what the body needs to balance.
Food shows up in that urine. In 1995 Remer and Manz worked out the potential renal acid load (PRAL) of common foods. Values ran from about 23.6 mEq per 100g for some hard cheeses, through 0 for fats and oils, to roughly -3 for fruits, fruit juices and vegetables. Net acid excretion tracked urine pH closely (r = .83), so the method can predict how a diet shifts the acidity of urine (PubMed 7797810).
So is alkaline food required?
Alkaline diets and products are marketed as a way to help the body regulate its pH, as Fenton and colleagues put it in 2011. Of 238 studies they found, 55 met their inclusion criteria, and they weighed that evidence using Hill's criteria for causality. They found no evidence that an alkaline diet is protective of bone health, and no study revealed a biologic mechanism working at physiological pH (PubMed 21529374). Schwalfenberg reached a similar point: alkaline diets give a more alkaline urine, but there is no substantial evidence that this improves bone health.
What his review does support is eating more fruit and vegetables, which would improve the ratio of potassium to sodium in the modern diet. And his conclusion comes back to the ground. One of the first considerations in an alkaline diet, he writes, is to know what type of soil the fruit and vegetables were grown in, since this may significantly influence their mineral content. He adds that there are limited scientific studies in this area.
Where dates fit
Remer's formula, as Schwalfenberg describes it, adds sulfate, chloride, phosphate and organic acids on one side and subtracts sodium, potassium, calcium and magnesium on the other. Dates are not in the review's PRAL table, so no score is given here. Their minerals are on record, though. USDA FoodData Central (SR Legacy record 171726) lists Deglet Noor dates at 656 mg potassium, 43 mg magnesium, 39 mg calcium, 62 mg phosphorus and 2 mg sodium per 100g. Deglet Noor comes from Tunisia and Algeria.
The NHS counts a 30g portion of dried fruit, naming dates, as 1 of your 5 A Day. It also says that portion should be eaten at mealtimes, not as a snack between meals, to reduce the impact on teeth.
Soft Mazafati dates come from Bam in Kerman province, Iran. They are dark and very soft, need refrigeration, and are cold-stored so they are sold all year. Kurma Mazafati Malaysia is a site that covers this variety.
The video below, from the YouTube channel AbuAyyash Farms, is titled "Amazing Medjool Dates Fruit Farming and Factory - Artificial Intelligence Date Processing Technology".
Before you change how you eat
This article is general reading, not personal advice. The NHS says that anyone with a medical condition or on a special diet for their health should talk to a GP or a healthcare professional before making changes to their lifestyle.
Kurma Borong Malaysia's about page says it handles everything from retail purchases to wholesale supply and delivers across the country. Questions, quotes and orders go through the WhatsApp number on the contact page, and more reading on dates sits on the Kurma Borong blog.