A bowl of lemons (file image)
Lemons are highly acidic, not alkaline, and have no effect on the COVID virus. Image by AP PHOTO

Claim high pH foods curb COVID is a lemon

William Summers February 2, 2024

People can protect themselves from COVID by eating highly alkaline foods.


False. COVID is not affected by bodily acidity. Eating alkaline foods won’t provide any direct protection against the virus.

A meme claiming people can beat COVID-19 by eating highly alkaline foods has resurfaced almost four years after appearing early in the pandemic.

The claim is false. The COVID virus is not affected by food acidity, with a virologist telling AAP FactCheck the claim is “rubbish”.

Eating alkaline foods will not cause anyone’s blood acidity levels to change in any meaningful way or protect them from viruses. Additionally, most of the foods recommended in the meme are actually acidic, not alkaline.

An Indonesian language version of the meme was posted to Facebook in 2020 and subsequently debunked by fact-checkers in Indonesia.

The English language version has appeared on social media repeatedly since 2020 (see here, here and here). An Australian user reposted it to Facebook on January 24, 2024.

A screenshot of the the Facebook post.
 The post’s claims are nonsense. 

“COVID-19 is immune to organisms with a pH greater than 5.5,” the English language version of the meme states.

“We need to consume more food alkalines that help us to increase the level of PH, to fight the virus.”

It lists seven foods claimed to have a high pH, including lemon (9.9 pH), avocado (15.6 pH), garlic (pH 13.2) and pineapple (12.7 pH).

The pH scale is a measure of how acidic or alkaline (‘basic’) a substance is, on a scale of zero to 14. A pH of less than seven indicates a substance is acidic while more than seven indicates it is alkaline or ‘basic’.

The post’s confused claim that COVID is “immune” to organisms with a pH above 5.5 could be a mistranslation from the Indonesian version of the meme.

The Indonesian version does not claim COVID is immune to alkaline foods but instead says the virus has a pH between 5.5 and 8.5.

Regardless, both the English and the Indonesian versions are false.

Garlic bulbs (file image)
 Garlic allegedly wards off vampires as well as COVID. 

A virus expert told AAP FactCheck the claim was “utter rubbish”.

“Looking at the screenshot, it’s not even using scientific nomenclature: pH is written PH, and lemons, replete with citric acid, are definitely not alkaline as claimed,” said Chris Smith, a clinical virologist at Cambridge University and the founder of a UK-based group of science communicators called The Naked Scientists.

Dr Smith said the pH of the bloodstream was tightly regulated and controlled by the kidneys to maintain a mildly alkaline state of 7.35-7.45.

While food can influence the pH level of urine, it won’t significantly change the pH of blood.

“Only in extreme situations does this (blood pH level) ever change. When it does, usually the person feels unwell,” Dr Smith said.

Stomach acid is about pH 1-2.

Dr Smith said while some viruses relied on exposure to stomach acid in order to infect the intestine, respiratory infections “are not seeing stomach contents”.

“And while what you eat does affect overall health and therefore resilience and susceptibility to infection, it’s garbage to claim that it’s anything to do with pH,” he said.

The meme lists various foods claimed to be highly alkaline. However, the pH values listed alongside the foods are all wrong.

Avocados (file image)
 The meme lists the pH of avocados as higher than bleach. 

Lemons are an acidic fruit with a pH value of around 2 to 3, not 9.9 as claimed.

Similarly, mango, tangerine, pineapple and orange are all acidic fruits with low pH values, not alkaline fruits with high pH values, as claimed in the meme (see fruit pH values here, here and here).

The pH values of the other food mentioned in the meme are similarly wrong.

The meme claims avocado has a pH of 15.6. If true, this would exceed the upper bounds of the 0-14 pH scale, making avocados more alkaline than household bleach and drain cleaner.

Simon Keely, an immunology and microbiology professor at the University of Newcastle, told AAP FactCheck there was no credibility to the meme’s central claim that a high-alkaline diet would protect people against COVID. 

“There may be some incidental benefit in that alkaline diets generally have higher levels of fresh fruit and veg and thus may promote healthier eating, leading to improved all round health,” Prof Keely said in an email.

“Generally speaking, people with better overall health, do better in fighting off infection.

“But there isn’t, as far as I can tell, any direct evidence that an alkaline diet leads to better health in a way that would protect against any infection, never mind COVID.”

The Verdict

The claim eating highly alkaline foods will help fight COVID is false.

Blood pH levels are stable at around 7.35-7.45. Eating alkaline foods won’t make any significant difference to blood acidity.

Virology and immunology experts told AAP FactCheck there is no evidence a high-alkaline diet provides any protection against COVID.

Additionally, the pH values the meme attributes to certain foods are all wrong. Most of the listed foods are acidic, not alkaline.

False – The claim is inaccurate.

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