Introduction 

When you think about antimicrobials, coconuts probably wouldn’t immediately spring to mind. The fact is, however, that coconut oil is the highest natural source of a type of fatty acid called lauric acid. This fatty acid has been researched for its anti-microbial activity, which is how it fights against bacteria, viruses, and fungi.

This article will delve into the science behind lauric acid and whether there are any health benefits to be derived from it. 

What is lauric acid

Fats are made of smaller things called fatty acids, and lauric acid is one of these. It is often classified as a medium-chain fatty acid; however, biologically speaking, it acts like a long-chain one, being absorbed by the body more slowly.¹ It has a slight odour of bay oil and is the main fatty acid found in coconut oil and palm kernel oil.²

Lauric acid can be used to make a chemical called monolaurin, which has been marketed to fight various health problems. Monolaurin is commonly used in cosmetics, food production, and the pharmaceutical industry; however, its uses are still being researched.

Coconuts as a source of lauric acid

Coconuts provide a source of saturated fat, the type usually found in meats.  As well as fats, they contain various minerals, including manganese, copper, selenium, and iron. Because of the high fat content, nutrition guidelines have in the past advised against high consumption, although it has witnessed a surge in popularity recently because of touted health benefits.³

Coconut oil is extracted from the “meat” of the coconut in various ways, can be eaten, and is found in more products than you may think. Its production has been increasing worldwide, with the UN estimating that more than 3 million tonnes were produced in 2019.⁴ It is composed mainly of lauric acid, accounting for 42  per 100 grams.⁵ Different extraction methods will produce different amounts of lauric acid, meaning it has different uses.

Heart health

As there is a lot of saturated fat in coconut oil, the blood concentration of the so-called “bad” cholesterol (LDL cholesterol) can increase from eating it, although it also increases the “good” cholesterol (HDL cholesterol). This could affect the cardiovascular system as LDL cholesterol is an established risk factor. An editorial that looked at several studies concluded that it should not be used as a regular cooking oil but could be used sparingly, and a recommendation would require a trial looking at cardiovascular events such as heart attack or stroke.¹

Antimicrobial properties of lauric acid

Lauric acid and monolaurin, the product that can be formed from it, have been shown to exhibit strong antimicrobial properties against a wide variety of pathogens (harmful bacteria, viruses, and others) in numerous studies. This has been proven both in studies conducted in a lab (in vitro) and in living things (in vivo). Lauric acid can also be found in breast milk and is one of the strongest antimicrobial agents present in it.⁶ 

Bacteria have structures surrounding them called cell walls, and lauric acid may interfere with the synthesis of some of these, thereby exerting an antimicrobial effect. Another group that lauric acid can negatively affect is a bacterium called P. mirabilis, as well as the harmful Clostridium difficile (which is a common cause of diarrhoea affecting people who have recently been treated with antibiotics).⁶

Acne is the most common disorder of human skin, and a bacterium called P. acnes plays a critical role in the development of inflammatory acne. One study using mouse models found lauric acid decreased the number of bacteria present when applied either intradermally (through the skin) or on the skin.⁷

Even patients with some of the most fragile skin – very preterm infants – can benefit from coconut oil. Authors of a study compared virgin coconut oil to regular skin treatment in a neonatal unit, finding the coconut oil group had improved skin condition, which may protect from harmful pathogens (they saw fewer cases of dangerous sepsis but statistically couldn’t conclude it was linked to the oil). They also predicted coconut oil may modulate the skin “microbiome” (the groups of microorganisms like bacteria living on the skin), but such data isn’t available to draw a firm conclusion.⁸

These are just some of the examples of lauric acid and monolaurin’s capabilities.

Viruses, particularly those with an envelope, are also susceptible to this fatty acid and its product, and include:⁹

• Herpes simplex virus 1 (HSV-1)
• HSV 2
• Vesicular stomatitis virus (VSV)
• HIV-1
• Mumps
• Yellow Fever
• Zika

Method of action 

There are multiple ways in which lauric acid is thought to work:¹⁰

• Destroying the cell walls of bacteria, which is also effective against the envelope that surrounds viruses.
• Inhibiting the pathogens’ cellular functions, so stopping them from developing.
• Preventing the pathogen from binding to a host cell.  If this binding never occurs, the virus is unable to infect and cause disease.

Does it help the immune system, too?

Because breastmilk is a highly effective mixture that helps ward off infection by supporting a baby’s developing immune system, it’s perhaps unsurprising that it contains a good amount of lauric acid. 

Studies have reported that lauric acid can influence various aspects of someone’s immune system. This ranges from their effects on the lining of the intestines to modulating how chemical signalling messengers for the immune system, called cytokines, are secreted. Cells that “eat” bacteria (called phagocytes) can also be given a boost in their activity due to lauric acid.¹¹

Fighting antimicrobial resistance

Drug-resistant tuberculosis (TB) is a growing threat to the world’s population since the drugs normally used to fight the infection have a reduced power to combat the disease. According to a 2023 study, when lauric acid was combined with an anti-TB drug, it was able to kill multidrug-resistant TB in vitro much quickly than the drug alone.¹²

It remains to be seen what role lauric acid will play in other conditions where drug resistance is a concern.

Coconuts in food and cooking

Coconuts are used for their water, milk, “meat” and oil. Since coconuts have a high fat content, they are calorie-dense, and it is recommended that they (and their oil) should be eaten in moderation. Coconut oil is roughly 86% saturated fat, making it have a higher saturated fat content than butter.

Having fewer carbohydrates than most other fruits, it can make up part of a ketogenic diet, which is a low-carbohydrate, high-fat diet that can be useful to treat certain conditions like type 2 diabetes. Remember that it is important to speak to a dietitian if you’ve been given a diet plan before making any alterations to it.

There is a similar oil called MCT oil, which contains medium-chain triglycerides and is usually made from coconut or palm kernel oil; however, unlike coconut oil, MCT oil does not contain lauric acid 

Supplements and dosage

Monolaurin is more effective at killing certain bacteria than lauric acid shown in in vitro studies (tests performed outside of a living organism), which may be why supplements containing it exist.¹³ Though it is classed by the US Food and Drug Administration as “generally regarded as safe”, details on a safe maximum dosage of monolaurin, nor what it can be specifically used for, have not been scientifically validated.

A review looking at the scientific literature surrounding its use as a dietary supplement was conducted in 2019 to explore the evidence for different vendors’ dosage suggestions. 190 articles were initially found, of which none were human clinical trials.  They then focused in-depth on 28 of those articles. These articles described the effects on animals and in vitro, and 3 investigated human topical use and antimicrobial action, with these being intravaginal (tampon) and intraoral (mouthwash). The authors concluded that there was no peer-reviewed evidence regarding human clinical applications for oral supplementation and urged the scientific community to explore claims about its use in the diet more thoroughly.¹³

Summary

Lauric acid is a fatty acid found in high amounts in coconuts with antimicrobial properties proven in some studies involving animals and others in vitro.  It affects bacteria, viruses and fungi by different mechanisms.  It may modulate the immune system and could be used in the future to target antibiotic-resistant bacteria.

Because coconuts are high in saturated fats, guidelines advise only a limited amount to be included in your diet because of the risk of cardiovascular problems resulting from a higher cholesterol level. 

Topical applications of coconut oil may help with skin problems, but you should talk to a healthcare professional before starting to use it in this way.

Although it is safe to consume in food, there is insufficient evidence of its usefulness in dietary supplements in the scientific literature.  Those who are pregnant or breastfeeding should especially speak to a doctor or pharmacist before taking supplements.

Apart from having a coconut allergy, there are no real risks of complications or side effects to consuming coconuts, so incorporating them into your diet in moderation may be beneficial.