Published on 24th September 2017


 

Christian Billinghurst finds out that the devil’s in the detail when it comes to health benefits

If one food group has left us confused, it’s fat; and possibly none more so than coconut oil. Hailed as a panacea for a range of health problems, coconut oil has recently been the new wonder-kid on the so-called superfood block, finding its way into processed foods such as vegan cheeses, and into our own kitchen pans. But if anything could have thrown its health halo into doubt, it was a statement this June from the American Heart Association (AHA) that saturated fat was detrimental to cardiovascular health.1

The statement followed a review of studies into saturated fat in general, but coconut oil was singled out for attention: bad news for the coconut oil industry, and confusing for those of us who just want to know if we should eat it or not.

Health claims

Not only has coconut oil been claimed to be good for skincare or dental health (the latter when used for ‘pulling’ which means swooshing it for several minutes around the mouth — said to remove harmful bacteria), but it has even been claimed to help with weight-loss.

This is down to it containing medium-chain triglycerides (MCTs), types of fatty acids, which are transported directly to the liver during the digestion process, where they are quickly metabolised, and so avoid getting deposited in fatty tissue.

Using coconut oil needs to be taken in the context of “a healthy eating package”

Overstated?

However, Linda Main, a dietetic advisor for Heart UK, says that coconut oil’s many perceived health benefits have been over-stated. “Some of the suggested health effects of coconut oil have been attributed to medium-chain triglycerides [MCTs],” she says. “MCTs are a kind of fat that is metabolised differently in the body. MCTs have been shown to be better at satisfying appetite, are lower in energy and are thought to help facilitate weight control when substituted for more traditional fats in the diet.”

Some studies have stated that coconut oil can be as much as 60 per cent medium-chain fatty acids (MCFAs).2,3 However, there is some disagreement as to what should be referred to as an MCFA. Main cites an article which states: “If both of these fatty acids [caproic and lauric acid] are included in the definition, coconut oil could be described as containing around 65 per cent MCFAs. However, it seems unlikely that lauric acid is oxidised immediately in the liver, a characteristic of C8–C10 fatty acids, because of its potent cholesterol-raising potential”.4

Main says that only 14 per cent of coconut oil’s fat “can truly be described [as] MCT”. And until there is consensus on coconut oil’s MCT content, the case for weight-loss benefits is yet to be closed.

But coconut oil is said to have other qualities. It has a slow spoil-time and is resistant to the rancidity process. Despite this, however, the World Health Organization (WHO) has promoted the use of vegetable oils in its place.

According to Heart UK, “studies have shown that the greatest cholesterol lowering occurs when saturated fats are replaced with unsaturated fats” and so is “concerned” about recent discussion and promotion of coconut oil in the press. 

It states: “Coconut oil, unlike most vegetable oils, is predominately a saturated fat (85 per cent saturated fat) and has been shown to have a negative effect on circulating cholesterol levels — a known independent risk factor for cardiovascular disease [CVD].” It goes on to state: “As much as 90 per cent of the fat in coconut oil is saturated, 6 per cent monounsaturated and 1.5 per cent polyunsaturated fat.

“Compare this with the saturated fat content of butter (52 per cent) and palm oil (50 per cent).”

A cholesterol conundrum

Policy guidelines promoted by the WHO and the AHA state that saturated fats such as coconut oil raise cholesterol and therefore increase the risk of CVD.
However, whilst human trials have demonstrated that coconut oil increases both total cholesterol and LDL (so-called ‘bad’ cholesterol) levels, one review stated that better indicators for measuring CVD risk (such as LDL-HDL ratio and triglyceride levels) were not affected even when comparing coconut oil to ‘healthy’ vegetable oils and ‘unhealthy’ butter.5

So, confusingly for the consumer, there is a growing opinion that the evidence associating saturated fats and CVD is inconclusive, as emerging studies appear to debunk traditional thinking.6
Following the AHA’s statement, some doctors and scientists were quick to question it. One critic is cardiologist and co-author of The Pioppi Diet, Dr Aseem Malhotra, who told Optimum Nutrition: “My responsibility is to patients and scientific integrity, and when you look at the evidence the first thing to say is that there is no evidence at all that saturated fats clog the arteries.” That “myth”, he says, has been “busted”.
He also questions the AHA’s statement as being based on “poor science” and cherry picked studies from decades ago — although ‘cherry picking’ data is a common accusation from both sides of the fat debate.

Busted?

“Of course coconut oil will affect [cholesterol],” says Malhotra. “It varies from person to person.” But data, he says, shows that when it raises LDL, it also increases HDL (so-called good cholesterol). And a high LDL level is not necessarily associated with heart disease.
Coconut oil consumption needs to be taken in the context of “a healthy eating package”, he says. “So that as long as you are following what I recommend, which is kind of a low refined carbohydrate Mediterranean diet, having some coconut oil is not going to cause you a problem.”
Malhotra also questions the economic background to the AHA’s report. “You have to question their motives when they are an organisation that receives a considerable amount of money from the drug industry. There is a huge industry that has developed around cholesterol-lowering drugs.”

This is an observation put forward by other critics, as it is noted that the AHA review was part-funded by major manufacturers of cholesterol-lowering medications, the Canola Oil Council, and the California Walnut Commission1 (all of which was declared).

“The other thing that is really concerning,” says Malhotra, “is promoting the consumption of vegetable oils or industrial seed oils on the basis that they lower cholesterol as effectively as statins.” He says that trials that lowered cholesterol by dietary changes, such as increasing vegetable oil consumption, did not reduce death rate, heart attack or the risk of stroke. Beyond the cholesterol debate, however, Malhotra says he can only look at the best available evidence that is there. “Like anything obviously consumed in moderate amounts, it is not harmful.

“I have a tablespoon of coconut oil in my coffee every morning. It keeps me full, it gives me energy... whatever, a nice replacement for sugar which is obviously much worse.”

Good for all?

Claims of other health benefits include coconut oil being associated with a reduced risk of Alzheimer’s disease. One study found that anti-inflammatory components in coconut oil can pass the blood-brain barrier with neuroprotective effects.7 However, the study in question only focussed on populations that already consumed large amounts of coconut oil. Similarly, studies that have associated coconut oil consumption with reduced cancer risk have tended to be conducted on animal models or non-western populations where overall diet and lifestyle may differ from that in the west.

“I would not go as far as to say that it’s a superfood and it has all these other properties”

Lifestyle factors may make all the difference. For example, whilst coconut oil is said to be better for cooking than other vegetable oils because it is resistant to oxidation and polymerisation (when small molecules join together to make long molecules, so result in a change in the chemical structure), this benefit is lost when cooking at high temperatures — such as in deep frying. Despite its stability, coconut oil also has a low smoke point (171C/350F)8 which is the temperature at which it produces smoke and toxins, so is only suitable for gentle or mid-heat frying.

As for beneficial antimicrobial properties, research has shown coconut oil can inhibit the growth of harmful bacteria at a cellular level which, in theory, would help with diarrhoea caused by antibiotic use.9  However, such studies have so far only been in small lab tests, and human studies have not shown any significant beneficial changes. It is perhaps no wonder that Heart UK states that the “health benefits of coconut oil are definitely over hyped”.

What's in a label? The cost of trying to be healthy

Cold pressed, virgin or extra virgin? If you have wondered which to buy, you are not alone. We contacted several coconut oil companies to find out what the difference was between these labels but received little response. One industry insider who did not wish to be named said that there was “almost no difference” between extra virgin and virgin coconut oil. Another said that extra virgin coconut oil was higher quality, but was unable to elaborate as to why. Still confused, we resorted to the internet.
One commentator, writing in coconutoil.com, says: “the only truly ‘unrefined’ coconut oil you can consume is the oil still inside the coconut meat from a fresh coconut just picked off the tree”,10 and that coconut oil can only be produced by three different methods: refined, bleached and deodorised (RBD); cold pressed; or wet milled.
Wet milled is considered to be the best because it does not require drying and heavy refinement. Research has shown that wet milled coconut oil contains higher amounts of antioxidants, but health comes at a price because this tends to be the most expensive.11
At the other end of the spectrum; RBD uses higher temperatures to extract the oil from the coconut meat (between 70-80C), and then treatment with chemicals to get rid of impurities and to deodorise it, but it is also the cheapest.
Cold pressed extraction is similar to RBD but uses lower temperatures to extract the oil (<48C) and therefore prevents some of the undesirable consequences of rancidity. This oil is generally marketed as virgin.
However, unlike olive oil, coconut oil quality is not classified through the term ‘virgin’. Effectively, anyone can label their coconut oil as virgin because standardisation currently does not exist. It may seem like a marketing ploy, but virgin coconut oil is usually cold pressed so considered higher quality. However, there is nothing to stop companies labelling RBD oil as virgin, which is why consumers should look for ‘cold pressed’ or ‘wet milled’ on the labels. The term ‘extra virgin’ appears to be irrelevant.
Until there is standardisation across the industry, method of processing appears to be the better indicator of quality, with organic wet milled reflecting higher quality and cold pressed a reasonable alternative.

“I would not go as far as to say that it’s a superfood and it has all these other properties,” says Malhotra. “There may be some evidence there, but I can’t go that far. But what I can say — as a cardiologist — is that consuming coconut oil in moderation as a part of what I call a low refined carbohydrate Mediterranean diet, will not do you any harm.

“I wouldn’t go as far as saying that I can tell you it is very good for you — that it is good for your health, but it can be very much part of a healthy diet.”

And it is probably such advice that we need to keep in mind. Coconut oil is only a tiny part of a much bigger picture, and if we are living on a diet of chips and little else, then frying them in coconut oil isn’t going to turn them into a healthy option.

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References

  1. Sacks FM et al (2017). Dietary fats and cardiovascular disease: a presidential advisory from the AHA. Circulation, 135(25). 
  2. Bhatnagar AS et al (2009). Fatty acid composition, oxidative stability, and radical scavenging activity of vegetable oil blends with coconut oil. J Am Oil Chem Soc. 86:991–999.
  3. Boateng L et al (2016). Coconut oil and palm oil’s role in nutr, health and nat dev: A review. Ghana Med J, 50.3 (2016): 189-196.
  4. C Lockyer S & Stanner S (2016). Coconut oil — a nutty idea? Nutr. Bulletin. onlinelibrary.wiley.com/doi/10.1111/nbu.12188/full
  5. Eyres L et al (2016). Coconut oil consumption and cardiovascular risk factors in humans. Nutr Rev, 74(4), 267-280. 
  6. Chowdhury R et al (2014). Association of dietary, circulating, and supplementing fatty acids with coronary risk: a systematic review and meta-analysis. Annals of Internal Med, 160(6), 398-406. 
  7. Fernando W et al (2015). The role of dietary coconut for the prevention and treatment of Alzheimer’s disease: potential mechanisms of action. British J of Nutr, 114(1), 1-14. 
  8. coconut-merchant.com/oil-smoke-points/
  9. Shilling M et al (2013). Antimicrobial effects of virgin coconut oil and its medium-chain fatty acids on Clostridium difficile. J of Med Food, 16(12), 1079-1085.
  10. coconutoil.com/what-type-of-coconut-oil-is-best-how-to-choose-a-coconut-oil/
  11. Marina AM et al (2009). Antioxidant capacity and phenolic acids of virgin coconut oil. Int J of Food Sciences and Nutr, 60, 114-123.