Lemon juice contains vitamin C, a vital nutrient. We've long-known a vitamin C deficiency can lead to scurvy. This condition is most commonly associated with seafarers in history who had no access to fresh fruit and vegetables on long voyages.
More recently, we have seen low levels of vitamin C in Australia, for instance in people admitted to hospital and referred for surgery. But this may not represent vitamin C levels more broadly in the community. In this group of people, the factors that led to their ill health could also have impacted their vitamin C intake.
If your intake of vitamin C is low, drinking lemon water may help. Vitamin C starts to degrade at 30-40℃, which would have a small impact on levels in your warm lemon water, but nothing too concerning.
If you have enough vitamin C in your diet, anything extra will be excreted as either vitamin C or oxalate via your urine.
Your body already detoxes without the added "help" of lemon water. Photo / Getty Images
What else can lemon juice do?
Lemon juice may have other benefits, but research so far has been mixed.
One study found people with high blood lipid (cholesterol) levels who drank lemon juice for eight weeks did not see any changes in their blood pressure, weight or blood lipids levels.
However, in another study, drinking 125mL lemon juice with bread led to a small decrease in blood glucose levels compared to drinking tea or water with the bread. A small study found something similar with drinking 30g lemon juice with water before eating rice.
Researchers suggest the acidity of lemon juice inhibits a particular enzyme in your saliva (salivary amylase), which usually starts to break down starch in your mouth. So it takes longer for starch to break down to glucose lower in the gut and transported across the intestine wall into your blood. For people with diabetes, this may lead to a reduction in the spikes of blood sugar levels, but it has not as yet been tested.
Other studies indicate there are other nutrients in lemon that may be beneficial for protecting against developing diabetes.
But it is likely you can get the same benefits by adding lemon juice to your food.
How about detoxing, energising or soothing?
Your body already detoxes without the added "help" of lemon water. It breaks down toxins or excess nutrients in the liver and eliminates those molecules via the kidneys and out into the toilet in your urine.
There is no evidence vitamin C helps this. So any claims lemon water detoxes you are untrue. If you really need a detox, you probably need a liver transplant.
Does lemon juice energise you? Aside from the placebo effect of drinking something you feel is good for you, the short answer is no. However, like most nutrients, if you're not getting enough of them, you could feel sapped of energy.
And as for lemon water being a soothing drink, some people find warm drinks soothing, others prefer cold. The best temperature to drink fluids is the temperature at which you are more likely to drink enough to stay hydrated.
Any possible harms?
As lemon water is acidic, there have been some concerns about its ability to erode tooth enamel. But this is a problem for any acidic beverages, including fizzy drinks and orange juice.
To minimise the risk of acid erosion, some dentists recommend measures including:
• rinsing out your mouth with tap water after drinking lemon water • chewing sugar-free gum afterwards to stimulate saliva production • avoid brushing your teeth immediately after drinking lemon water • drinking via a straw to avoid contact with the teeth
Some doctors say lemon water may irritate the bladder and may make some people feel like they need to urinate more often, particularly at night. If that's the case, they recommend switching to plain water.
However one study, which looked at a range of drinks including lemon beverages, found no effects on bladder irritation when people reduced their intake.
Others say lemon water makes acid reflux (heartburn) worse. But this has not been tested.
So, should I drink lemon water?
If you enjoy drinking lemon water, drink it! But if you don't like drinking it, you're not missing out.
You can get your vitamin C from other citrus fruits, as well as other fruit and vegetables. You can also squeeze some lemon juice on your meat, salads or vegetables.
