When I think of Mediterranean food, it makes my mouth water: I think of sun-ripened tomatoes, artichokes, fruit bursting with flavour, nuts, seeds and delicious olive oil. And this diet is proving to be very good for health which means that not everything that tastes great is bad for you!
However, the famous Mediterranean diet contains quite a bit of fat, the monounsaturated variety from olive oil, polyunsaturated oils from cold water fish, but also saturated fat from nuts and seeds, not to mention pancetta that Italians love, or chorizo, the popular Spanish sausage that everyone is familiar with. Nutrition experts tend to gloss over the last two food items mentioned but in reality Mediterranean people love their red meat. So is this diet, and the balance of fats in it, good for you?
If you had any doubt, a new study published in the journal Progress in Cardiovascular Disease has confirmed the health benefits of a Mediterranean diet. The study was carried out in Spain and followed 7447 people – men between the ages of 55 and 75 and women between the ages of 60 and 80 years old. They were randomly split into 3 groups and assigned one of three diets which were: The Mediterranean diet supplemented with Extra Virgin Olive Oil; The Mediterranean diet with nuts and the control group was given advice on following a low-fat diet. The scientists found both Mediterranean diets supplemented with oil and nuts reduced heart disease by 30% compared to the low-fat diet.
A similar study published in the British Medical Journal (BJM) shows that the Mediterranean diet has anti-ageing benefits, being associated with longer telomeres, a marker of good health and longevity.
Eating olive oil, fish and nuts raises levels of high-density lipoprotein (HDL) – which is more commonly known as good cholesterol, one of the things doctors test for when predicting your risk of a heart attack. It’s the low-density lipoprotein (LDL) or bad cholesterol we are told to fear. Why? To make a long story short: the good cholesterol has the duty to collect the bad cholesterol from the blood stream and take it to the liver to be metabolised or detoxified (turned into a harmless molecule and eliminated in bile).
Recently though, the discovery of a specific gene in some individuals, SCARB1, cast a lot of doubt over good cholesterol as well, as a BBC Health article recently announced.
To help shed some light on the current cholesterol craze, it’s important to go back in medical history and find out how the correlation between cholesterol and heart disease was established in the first place.
The Cholesterol Theory
The idea that high cholesterol causes heart disease can be traced back to Rudolph Virchow (1821-1902), a German pathologist who found thickening in the arteries in people he autopsied, which he ascribed to a collection of cholesterol. His hypothesis was embraced by Ancel Keys (1904-2004), a well-known physiologist who published his seminal paper known as the “Seven Countries Study” in 1963. This first major report linking saturated animal fat consumption to heart disease served as the basis for nearly all of the initial scientific support for the Cholesterol Theory.
However, what many don’t know is that data was actually available from 22 countries, but Keys selectively analysed information from only seven of them. The seven countries chosen held true to his initial theory.Upon later analysis, other researchers discovered that when all 22 countries are included, there’s no correlation at all between saturated fat consumption and coronary heart disease. Another observation that supports the latter theory is that, despite people eagerly adopting the low-fat diet fad, rates of heart disease have stayed on a steady increase.
There are also other problems with the Cholesterol Theory. To establish a directly causal link between cholesterol intake and heart disease is too simple a hypothesis: it amounts to saying that the cholesterol found in the arteries is a direct consequence of excess cholesterol in the diet. But this is to ignore other factors that might be influencing this outcome. And there might be a multitude of other factors, such as liver function: if your liver is toxic and malfunctioning, it could synthesise a lot more cholesterol than you need. Also, calcium metabolism has an impact on cholesterol levels, as this study published in PubMED demonstrates. Beneficial effects of calcium phosphate supplementation on cholesterol metabolism were shown in many studies such as this trial carried out by the American Society of Nutritional Sciences. Also, how about the involvement of negative emotions such as anger, anxiety, and depression and the release of stress hormones in CHD, as suggested in this study?
Still, the Cholesterol Theory dominated the scientific mindset for a long time. Fat is abhorred to the point it was virtually removed entirely from the latest USDA “food pyramid”. Except for a small portion of dairy, which is advised to be fat-free or low-fat, fats are missing entirely.
However, a handful of recent reports have muddied the link between saturated fat and heart disease. One meta-analysis of 21 studies said that there was not enough evidence to conclude that saturated fat increases the risk of heart disease, but that replacing saturated fat with polyunsaturated fat may indeed reduce risk of heart disease.
Why Your Body Needs Fat
Fat is a major source of energy. It helps you absorb some vitamins and minerals. Vitamin D for instance is synthesised from cholesterol. Fat is needed to build cell membranes, the vital exterior of each cell. Cholesterol is particularly abundant in nerve and brain tissue where it participates in the creation of the protective sheaths surrounding nerves. Fat is essential for blood clotting, muscle movement, and inflammation. But for long-term health, some fats are better than others.
To the extent of our knowledge today, good fats include monounsaturated and polyunsaturated fats, bad ones include industrial-made, trans fats, and saturated fats fall somewhere in the middle.
More About Saturated Fats
Saturated fat are solid at room temperature. Common sources include red meat, whole milk and other whole-milk dairy foods, cheese, nuts and seeds, coconut oil, etc.
The word “saturated” refers to the number of hydrogen atoms surrounding each carbon atom. The chain of carbon atoms holds as many hydrogen atoms as possible — it’s saturated with hydrogens. This makes them very stable chemically, unlike the polyunsaturated fats (PUFAs) that oxidise very easily, a process that makes PUFAs become toxic.
This is not to say however that I’m not encouraging a diet rich in saturated fats, I’m just acknowledging its usefulness in the body, something that usually gets ignored. A diet that is very high in saturated fat may potentially drive up total cholesterol and tip the balance toward more harmful LDL cholesterol, which prompts blockages to form in arteries in the heart and elsewhere in the body.
But it seems that it all depends on your genes. Think of the Inuit paradox: Eskimos get a lot of their calories from saturated fat. However, 1) you’re not an Eskimo!, and 2) they also consume a high amount of omega 3 oils that are known to be protective against heart disease. So it would be wise to conclude that it’s more about the balance of different types of fat in the body.
Talking about genetics, the recent discovery of a mutation in the SCARB1 gene is bad news as individuals with this genetic mutation are at much higher risk of heart disease due to their bodies’ mishandling of good cholesterol, as this research study shows. The mutation in the gene prevents the good cholesterol HDL from dumping the fat it had collected in the liver for processing.
That is why “general” nutrition advice is not a good idea in every case. Moderation and a “balanced diet” might work for some but not for everyone.You always hear stories of people who always minded their fat intake and followed a “generally healthy diet” but still died young of a heart attack. Is it possible they had this gene?
This is also why a personalised diet based on genetic testing makes perfect sense. It will help you pin down all the genetic factors that might predispose you to bad health and you will be able to take dietary measures accordingly. This will also help motivate you to stick to a diet.
If you’re interested to know more about genetic testing, please drop us an email at firstname.lastname@example.org