Lilac and vanilla?
The article today is about curiosities. For years, I have noticed lilac flowers in my region tend to smell a lot like vanilla after a rainstorm. But this effect is not observed in other parts of the world. As it turned out, this is not a personal foible but a minor peculiarity with an unusual scientific explanation. However, the smell of lilac is a personal curiosity and not this week’s main subject, though if you are curious, the reason is at the end of this article.
So, this week’s column is a story about another curiosity regarding triglycerides, or more accurately, what they were doing in my blood. Some years ago, as part of my normal health screening, a blood test revealed that I had elevated levels of triglycerides. This is a sign of metabolic syndrome, and there is an important explanatory story in my previous article ‘TOFI, FOFI and metabolic syndrome’.
As I was somewhat overweight at the time, I adjusted my food intake down by a few hundred calories and exercised more to get fitter and burn away excess glucose and triglycerides. This helped me to lose around five kilos in weight after a lot of effort over a few months, but a second test indicated only a minimal improvement; the levels of blood triglycerides were still above normal. This did not make sense as the amount of exercise had easily offset the calories in my diet, and there was also a physical loss of weight to indicate dieting had had a “positive” effect.
More research into this odd situation led to a disconcerting conclusion. Burning/reducing calories may result in some short-term weight loss but exercise and cutting calories do not necessarily mean improvement in metabolic health. Basically, exercise and dieting were causing my body to change from FOFI (Fat Outside, Fat Inside) to TOFI (Thinner Outside, Fat Inside), and it was the “Fat Inside” condition which was still causing the elevated levels of triglycerides in the blood.
So how does this happen? There are several causes, such as underlying genetics, or some disease, but those are not usually the reasons. In most cases, the undeniable causes of metabolic syndrome are overindulgence in processed foods, immoderate sugar consumption and excessive fat intake (especially from fried foods). And calorie reduction does very little to mitigate the causes of metabolic syndrome without some accompanying simple (but profound) changes to the diet.
In short, a lousy diet packed with processed carbohydrates, sugars and fats is not something one can exercise away or outrun. And it turns out that the supporting scientific evidence against such foods has been hiding in plain sight for years, but people are often distracted from understanding the significance of the health information available.
Unlike cigarette packets, there are no horrible pictures of diseased organs arising from overeating chocolate bars or overdrinking fizzy beverages on food packaging, for example. The general lack of awareness of metabolic syndrome may also be due to the lengthy period required before it becomes a significant health issue to individuals. And yet, metabolic syndrome takes up far more medical resources than all other diseases combined. Some 75% of the total healthcare costs in the USA are currently related to treating maladies arising from metabolic syndrome.
Where lipids come from, and why
Let us start by understanding how triglycerides end up in the blood and why they are a common marker for metabolic syndrome. Firstly, triglycerides are a type of fat, also known as lipids, consisting of three fatty acids bound to a glycerol backbone. They are the most common type of fat in the human body, occasionally acquired by eating fatty foods in our Paleolithic past and stored in fat cells as an important energy reserve.
Therefore, one simple way to lower blood lipids is to eat less fat, and perhaps eating only up to 30% of the total daily calories as fats is an acceptable amount, according to the UK National Health Service. Even more fat may be allowed as not all fats are equal. Omega-3 fats are zealously hoarded by the body and are not known to cause any harm (quite the opposite, in fact), therefore eating more oily fish is not the same as eating an extra portion of deep-fried nuggets.
As part of the normal processing of dietary fats, the liver converts them relatively easily into lipids which circulate in the blood to be stored as subcutaneous adipose tissue (under the skin), or visceral adipose tissue (around the belly), or at the last resort as ectopic fat (other unsuitable places like the liver). Metabolic syndrome happens when even the ectopic fat storage capacity is overloaded.
In many cases, the problem is not caused by eating too much fat, but by eating too much processed carbohydrates and sugars. This causes a surge in glucose levels in the blood, causing a corresponding flood of insulin to be issued by the pancreas to counter the glucose. Excess blood glucose is toxic to the body and insulin promotes the uptake of glucose by various tissues, thus removing glucose from the blood. Under normal circumstances, insulin simply balances glucose blood levels by ensuring that glucose is absorbed by tissues which then use it for energy.
But excessive glucose blood levels are another matter entirely because it necessarily involves removal of excess glucose via complex processes such as glycolysis and lipogenesis in the liver. These are fascinating topics but too convoluted to explain here.
However, one should be aware that 100 grams of carbohydrates or sugar can potentially generate up to 200 grams of triglycerides during the transformation of glucose into lipids (lipogenesis) by the liver. And many people tend to consume bad diets with more processed carbohydrates and sugars than fats. As a result, the real impact of bad diets is that they cause the liver to work harder due to lipogenesis, and more triglycerides get produced and deposited around the body as fat cells until there is no space left to store them, and then the leftover lipids remain in the blood, as a clear marker of metabolic syndrome.
Regarding the problem with excess blood lipids, the remedy was simply to abandon refined carbohydrates and excess fats and eat real/natural food, especially those high in natural dietary fibre. The reason is dietary fibre slows down food digestion, feeds human gut bacteria (which improves the immune system and causes the absorption of more nutrients) and causes a slower release of fats and glucose into the body. A subsequent test confirmed a 20% drop in blood triglycerides to safer levels, at 1.53 mmol/L from the earlier 1.92 mmol/L.
There are two kinds of dietary fibres: insoluble, and soluble. Both are important but soluble fibre is usually less available. Most processed foods with added fibre would tend to include an insoluble fibre called cellulose because it is cheaply derived from tree wood. But if you do not want to eat ground-up wood shavings, then the best natural sources of insoluble fibre are nuts, whole grains, fruits, and vegetables.
It is also beneficial to add some soluble fibre to the diet. Some types of soluble fibres are pectins (found in fresh fruits, vegetables, etc), beta-glucans (oats, barley, etc), inulin (leeks, chicory root, etc) and fructans (onions, garlic, etc).
Apart from pectins, the other types of soluble fibre can require some cooking to render them more digestible. Both soluble and insoluble fibres are generally not affected by cooking heat, but soluble fibres MUST NOT be heated in an acidic solution because the fibres will decompose into sugars.
Mostly true summary
Despite the common hype that calorie reduction and exercise are good for health, the likely reality is this is not always wholly true. One reason is a process called metabolic adaptation which refers to the physiological changes caused by changes in energy balance, such as a reduction in calories and/or an increase in physical activity.
Metabolic adaptation means the body adapts to being more efficient in using energy during periods of calorie restriction and/or high energy expenditure, meaning that it burns fewer calories both at rest and/or when exercising. This potentially means leaving more glucose and triglycerides in the blood, resulting in little improvement of any metabolic syndrome condition without a change of diet. Metabolic adaptation is the reason why weight loss usually happens quickly at the beginning of a diet/exercise regime, but weight reduction plateaus off after a short period unless the amount of exercise is constantly and significantly increasing.
And for the eternally curious, here is why lilac sometimes smells like vanilla. Lilac flowers contain a compound called “syringaldehyde” which confers their characteristic scent. When it rains, this compound attaches to the moisture in the air and becomes more volatile, intensifying its fragrance.
But the reason why lilac can smell like vanilla is because of another compound called “geosmin”, which is produced by certain ground-based microorganisms and can give the earth around the lilac plant a fresh, earthy smell. The combination of syringaldehyde and geosmin in a humid environment creates an aroma similar to vanilla. Not all ground contains flora (cyanobacteria, actinomycetes, fungi, etc) which produces geosmin, so not all lilac plants can smell like vanilla.
The views expressed here are entirely the writer’s own.