Limonene, the Compound in Lemons with Surprising Benefits

More and more, we’re starting to recognize that the foods we eat contribute to our health.

This is especially true for fruits and vegetables, as they contain a range of plant-based compounds, many of which have been linked to specific health benefits.

Now, you’ve probably heard many examples of this pattern, such as the way that both kale and pomegranates are often viewed as superfoods.

But, what about lemons?

Certainly, lemons don’t have the same amazing reputation that many other fruits have. Instead, lemons often get overlooked and are only really used when we’re looking for their sharp flavor - although sometimes lemons are viewed as a weight loss food (particularly in relation to lemon water). 

So, why are lemons good for you?

Because they are. In fact, they offer more health benefits than most people realize. Those benefits aren’t only connected to the juice either. Instead, there’s even an argument for eating the entire lemon, skin and all.

If we’re asking the question ‘why are lemons good for you?’, then the first place to start is with the compounds that lemons contain. This includes the nutrients that we commonly recognize, like vitamin C, along with compounds that are less well known, particularly limonene.

As you can probably imagine, the name limonene is a direct reference to lemons, as the compound is particularly prevalent in the rind of a lemon. However, limonene is also found in other citrus fruits.

One interesting thing about limonene is that it has a citrus odor. Because of this, it is often used in cosmetics and also in a range of other items, such as fragrance, bath products and even medicine.

The compound also has a number of other uses, including use as a solvent for 3D printing and for cleaning.

But, limonene is also relevant because of its potential health benefits. For example, early research suggests that limonene may help to fight fatty acid buildup in rats and similar outcomes may also be present in humans (1).

At the same time, the compound has also been linked to the ability to promote weight loss and to help reduce the risk of cancer (2).

So, limonene is actually a pretty important part of the answer to ‘why are lemons good for you’.

But, beyond limonene, there are also some other interesting compounds in lemons. For example, two plant chemicals called hesperidin and diosmin have been found in lemons and these may play a role in lowering cholesterol levels (3,4).

Likewise, lemons are also a key source of vitamin C, which has long been recognized as important for human health, including heart health, immunity and even eye health (5).

The Location of Nutrients

Now, it’s important to note that the specific nutrients and their amounts do vary depending on the part of the lemon that you are eating. As is often the case, this means that relatively few nutrients are present in the juice alone.

Indeed, fruit juice, in general, isn’t as healthy as it seems because it is lacking many of the nutrients that the whole fruit offers, while also tending to be high in sugar and calories. In the case of lemon juice, sugar isn’t such a concern but you’re still getting relatively few nutrients with just the juice.

One way around this is to include a significant amount of pulp along with the juice.

Doing so gives you access to more nutrients, especially as you are getting fiber from the pulp as well. As such, this type of juice will tend to be healthier than standard juice.

There is also another variation, sometimes called Mediterranean-style lemonade. In this case, the drink is made using the entire lemon.

One recipe for this idea can be found at The Mediterranean Dish.

This style of lemonade means that you are getting considerably more nutrients, including much more limonene (6). As such, it would be the best approach for getting nutrients, although some people may find that the taste and texture takes a while to get used to.

Health Benefits of Lemons

The compounds present in lemons go a long way towards answering the question ‘why are lemons good for you?’. After all, these compounds play a role in a number of health benefits. With that in mind, let’s take a look at precisely what benefits lemons actually have to offer.

Improved Heart Health

One interesting benefit of lemons is that they are associated with a decrease in some risk factors for heart disease. There are a few key reasons for this. One reason is simply that relying heavily on fruit and vegetables in your diet does tend to reduce heart disease risk, with green leafy vegetables and fruit high in vitamin C having the strongest effect (7).

However, that’s not all.

The fiber in lemons may also play a role in this effect, as one study showed that citrus fiber extract helped to decrease levels of cholesterol in humans (8). At the same time, the compounds of hesperidin and diosmin that I mentioned earlier also have a similar effect (9,10).

Additionally, some research suggests that flavonoids from citrus fruit can also help improve some heart disease risk factors (11).

Weight Loss Potential

From time to time, you may hear lemons promoted as a way of losing weight. There is actually some potential behind this concept and lemons may be relevant for weight loss in a few different ways.

The first area of consideration is pectin. Pectin is a structural compound that is found within plant walls and acts as a key source of dietary fiber. As such, the compound has the potential to help people to feel full.

However, because the compound is mostly found in plant walls, you won’t find a lot of it simply in lemon juice. This suggests the importance of also consuming the lemon pulp or, ideally, the whole lemon.

Other plant-based compounds in lemon may also be relevant for weight loss, including polyphenols (12) and flavonoids (13)

Another direction to consider is the idea that you can lose weight drinking hot or cold water with lemon juice. There is some evidence that drinking lemon water like this can help with weight loss but those benefits mostly come from the water, not the lemons (14). In fact, with lemon water you aren’t really consuming enough lemon to get many of the health benefits that lemons offer.

Instead, most of the benefits of lemon water are instead associated with the water itself.

After all, water does tend to be fairly filling and it may be especially relevant for weight loss simply because so many people don’t get enough water. Likewise, some research suggests that water can promote energy burning (15,16), which also supports its role in weight loss.

Lemon water is actually especially appealing because of that pattern, as the inclusion of some lemon juice can make water more appealing than it would be otherwise.

Helps to Fight Disease Development

As with many other types of fruit, some of the compounds in lemons act as antioxidants.

Now, I’m sure you’ve heard that term before, as antioxidants have become fairly popular as a way to promote health. Essentially, these are just compounds that fight the process of oxidation. While oxidation is natural, too much oxidation can potentially cause major health issues.

For this reason, antioxidants are promoted as a way to improve health and reduce the risk of disease development. This makes it important to get enough antioxidants (17).

However, it is also important to make sure your antioxidants come from natural foods that you consume, not from supplements. Indeed, there is growing evidence that antioxidant supplements may be too much of a good thing and, as such, may actually cause harm.

So, what about lemons?

Well, lemons might not be as powerful as tart cherries or blueberries in terms of antioxidants but they still act as a key source of antioxidants. Some of this comes from vitamin C, which is an antioxidant, although there are other compounds that have a similar function as well.

Indeed, some research has highlighted the antioxidant ability of lemons and citrus fruit in general, although more research is needed to identify the specific compounds involved in those actions (18,19).

At the same time, research has also suggested that lemons may have a role in fighting inflammation (20,21,22,23). Now, inflammation is another natural biological process that can have negative implications for health and contribute to disease development in some situations. As such, finding natural approaches to fight inflammation is important for health overall and lemons are one way of doing just that.

For example, inflammation is strongly associated with osteoarthritis and some research suggests that limonene may play a role in helping to slow down some aspects of cartilage destruction that occurs with osteoarthritis (24).

There is also some evidence suggesting that the antioxidant impact of limonene may play a role in fighting stress, although the research focused on the use of limonene as a supplement – rather than consuming the compound through lemons (25).

One unexpected benefit of lemons, particularly the compound limonene, is that there is the potential to fight against cancer (26,27).

Now, as a general rule, research into cancer is difficult, especially when it comes to cancer prevention. Because of this, there is still a lot that we do not know about the connection between lemons and cancer, and the outcomes of current research have been fairly mixed.

But, there is still some evidence that the compounds in lemon, particularly limonene, may help to fight cancer (28,29,30,31).

However, most of the research has focused on using high concentrations of the compounds found in lemon and other citrus fruit. As such, it isn’t clear what benefits would be associated with eating lemons or drinking lemon juice.

Nevertheless, the research does show that the compounds have potential and this serves to reinforce the idea that the nutrients in lemons are good for health overall.

Eating Lemon Peel

As with other types of citrus fruit, most people choose to use just the juice of lemons or the juice combined with the pulp. This means that we tend to leave the peel of the lemon alone, unless it is being used as a garnish for a drink.

However, lemon rind actually offers a surprising amount of health benefits, especially in terms of heart health. For example, research has indicated that lemon peels can be extremely relevant in helping to lower cholesterol (32). That outcome has been connected to the pectin in the rind and may also be due to other compounds, such as limonene (33,34).

At the same time, lemon peel is particularly relevant for health because of the soluble fiber it contains, much of which is pectin. That type of fiber is one of the key reasons why lemons tend to be associated with weight loss benefits and may also be associated with improved gut health and reductions in blood sugar (35,36,37).

Additionally, lemon peel shares many of the same compounds as lemon juice and pulp, but may have higher concentrations of some of them, like the limonene. Because of this, lemon peel helps to promote the same health benefits that I discussed in the previous section.

In fact, you really need to be consuming the lemon peel as well if you’re wanting any of the health benefits that come from limonene (38). In many cases, you would get little to no limonene if you just consume lemon juice (39).

Getting lemon peel into your diet may seem a little challenging but the Mediterranean-style juice approach is one way and seems to be the most powerful approach (40). However, there are also recipes out there that do use lemon peel as an ingredient, so this may be another appealing approach.

The site Local Kitchen Blog offers a range of ideas for using citrus peels and links to many recipes that you can try out. 

An important area to consider with lemons is whether you choose to have organic lemons or not. Now, if you’re just planning to have the juice from a lemon or even the pulp, then you’re probably okay with a non-organic lemon if that’s what you want.

However, if you’re planning to eat the lemon rind as well, then it’s best to stick with organic lemons. You also want to make sure that the lemons don’t have a wax outer coating, as many lemons do.

That wax coating is used to keep lemons looking good as they are shipped and handled.

Avoiding that coating is important, as it really isn’t something you want to be eating.

At the same time, if herbicides or pesticides were used in growing the lemon then it’s likely that some of these will be present in the skin. That’s what makes picking organic lemons such an important aim.

Even then, it’s critical that you wash your lemons carefully.

The Issue of Oxalates and Crystallization

Another thing to be aware of is that lemon skins have relatively high levels of oxalates. This isn’t a major issue in itself but when people have a buildup of oxalates they can begin to crystallize, playing a role in the development of gallstones and kidney stones.

With that in mind, you should avoid lemon peel if you have issues with gallstones or kidney stones, or if you know that you are sensitive to oxalate crystallization.

However, even if this is the case for you, it just means that you should avoid lemon peel because that’s where the concentration of oxalates is.

In fact, lemon juice may even play a role in helping to prevent the formation of kidney stones.

Research in this area is still ongoing but citric acid may be particularly significant in stopping these stones from developing.

The key reason for this is that citric acid can help increase the pH of urine, creating a less favorable environment for the creation of kidney stones (41,42).

However, research outcomes on this topic have been mixed, with some studies showing a positive effect from lemon juice or lemonade, while other studies have failed to find this outcome (43,44,45,46).

Why Are Lemons Good for You?

Traditionally, lemons don’t tend to be viewed as nutritious or good for health, yet that’s precisely what they are. Those key benefits include their ability to promote heart health, to act as an antioxidant and an anti-inflammatory agent, along with the potential to help with weight loss and even to fight cancer.

Those various benefits are strongly connected to the various nutrients and plant-based compounds that lemons contain, including limonene.

At the same time, there is still much we have to learn about lemons and their impacts on health. In particular, research on limonene and its connection to health is still in its relatively early stages and there may well be considerable health benefits associated with the compound that have not yet been discovered.

Despite the limited nature of current research, it is still clear that lemons are good for health.

Realistically, they are something that many of us should be eating more often and ideally we need to focus on lemon peel as well as the pulp and the juice.

If you can’t stomach eating lemons outright or you want to try and avoid their rather intense nature, there are certainly many other ways of including them in your diet, such as various recipes, along with the potential to make Mediterranean-style lemonade or to include lemon juice and pulp in smoothies.