A daily lemon is not a miracle, but one of its compounds already has a clinical role. Citrate, the main organic salt in lemon juice, raises the citrate that ends up in urine. Higher urinary citrate helps prevent calcium kidney stones from returning.
A 2021 narrative review in Nutrients reported that orange, grapefruit and lemon juices all increased urinary citrate levels in clinical studies. Lemon juice's effect was more modest than orange juice's, but a protective role showed up consistently.
According to Cleveland Clinic, two substances in lemons, citric acid and vitamin C, change urine chemistry in a way that makes stones less likely to form.
The vitamin C in a single lemon sits well within safe intake. Very high-dose supplements are a different story and have been linked to a higher kidney stone risk.
Also read: Fatty liver disease may affect 1 in 3 adults: 7 subtle clues doctors want you to know
Vitamin C and heart risk, honestly framed
A lemon delivers about 44.5 milligrams of vitamin C, nearly half of the daily value, Cleveland Clinic reports.
Large prospective cohort studies, including the Nurses' Health Study and the Health Professionals Follow-up Study, have found modest inverse associations between vitamin C intake and coronary heart disease. But a 2020 update in the journal Antioxidants noted that randomized trials of vitamin C supplements have not confirmed clear protection against major cardiovascular events. The food link is stronger than the pill link.
Blood pressure evidence is mostly in rats so far
The most eye-catching lemon claim, that it lowers blood pressure, rests on thinner ground. A 2023 study in Nutrients showed that citric acid and lemon juice reduced systolic and diastolic blood pressure in spontaneously hypertensive rats, with citric acid identified as the main active component.
The authors wrote that human studies are needed to confirm the findings. Lemon flavonoids such as eriocitrin and hesperidin can inhibit an enzyme involved in blood pressure regulation, but human evidence for lemon juice alone lowering pressure remains limited.
Also read: 8 warning signs of ulcerative colitis most people confuse with IBS
Who should be careful, and how to protect your teeth
Not everyone tolerates daily citrus. Cleveland Clinic includes citrus fruits such as oranges, grapefruit, lemons and limes among the acidic foods people with gastroesophageal reflux disease, or GERD, may want to limit, because the acid can irritate the esophagus.
There is also an enamel problem. Lemon juice has a pH of around 2 to 3, in the same range as soda. Frequent sipping softens enamel and gradually wears it down, and enamel does not grow back once it is lost.
Dentists recommend diluting lemon juice in a full glass of water, using a straw to limit contact with teeth, rinsing your mouth with plain water afterward, and waiting at least an hour before brushing, because scrubbing softened enamel can speed erosion.
Also read: 7 warning signs of frozen shoulder most people push through for months
Also read: What a pinched nerve actually feels like: 7 warning signs by location
This article is made and published by Jesper Bengtson, who may have used AI in the preparation.