Blood Sugar Rollercoaster—’The Silent Rust’

Sugar affects not only on how you feel, but also on how you look. Here are some of its outcomes:

• Faster skin ageing and wrinkles from cellular ‘rusting’ via a process called ‘glycation’, where sugar attaches to protein and fats inside the body (and most of our body is made up of those two!), forming ‘advanced glycation end products’, short ‘AGEs’, literally ‘aging’ us!

• Belly fat accumulation, despite being overall slim, aka ‘skinny fat’: Even if your overall caloric intake is low, these spikes and dips wreak havoc on your metabolism and send signals to your body to hoard fat around your belly (similar to what happens when there is inflammation!)

• Male pattern hairloss in men (R)

• PCOS symptoms in girls and women, such as acne and excess hair growth

And while these effects are unpleasant, and can contribute to you not feeling nor looking your best, if these blood sugar issues persist and happen frequently over years and decades, they much like inflammation, gradually cause our cells to ‘rust’, and the cogwheel machinery of health to clog up.

Some of the effects of sugar on health:

1. Chronic inflammation and increased risk of brain and mental health issues

High levels of blood glucose have been shown to upregulate certain immune cells, causing inflammation (R), and with it inflammation’s detrimental health effects.

Research indicates that dietary sugars and mixed processed foods may be a key factor leading to the occurrence and aggravation of inflammation (R). 

Chronic neuroinflammation (via activation of microglia and astrocytes, important cells in the brain) contributes to nerve cell loss and disease progression in Alzheimer’s disease.

• Recent research has identified high blood glucose (hyperglycemia) and the phenomenon of insulin resistance as two of the major factors contributing to an increased risk of Alzheimer’s disease. Alzheimer’s disease has even been nicknamed as ‘type 3 diabetes’, due to its high correlation with blood sugar swings and insulin resistance (R). 

• In research done by Bukhari and his colleagues, they found that mothers’ high-fructose diets influenced neonatal immunity and altered anxiety behaviour and inflammation in adolescence and adulthood. The study suggests that maternal diet may alter peripheral inflammation in newborns, which in turn affects anxiety-like behaviour and peripheral inflammation during adolescence. These findings reveal the lasting effects of a mother’s diet on her offspring’s immune system, meaning that the mother’s diet is crucial for their child (R). 

2. Lowered immune system function, increased infection and cancer risk

While chronic inflammation is an overtly upregulated immune system, blood sugar spikes have also been shown to at the same time render other immune cells less efficient, thereby tampering with our immune system’s response to invaders such as bacterial and viral infections (R).

Worse yet, this reduced ‘immune surveillance’ also slows its response to tumor cells, allowing a process termed ‘immune escape’ (R).

Recently, it was demonstrated that excessive consumption of high fructose corn syrup is associated with colon cancer development. In the study, mice fed with high fructose corn syrup had significantly increased tumor size (R, R, R, R).

3. A shift in the immune system towards autoimmunity

At the same time, on the contrary, it also reduces immune tolerance, turning the immune system ‘angry’ and attacking the wrong things – such as our own organs. This contributes to the development of autoimmune disease (R).

Common autoimmune diseases include rheumatoid arthritis, multiple sclerosis, psoriasis, Hashimoto’s and inflammatory bowel disease (IBD).

In recent years, numerous studies have shown that sugar-sweetened beverages play a key role in the development of autoimmune conditions and a shift of the immune system towards the autoimmune favouring Th17 response.

High consumption of glucose, fructose, and sugar-sweetened beverages is also known to reduce the beneficial flora in the gut and increase autoimmune triggering bacteria, such as Prevotella. 

It has further been found that high-glucose and high-sucrose diets can aggravate the disease progression of experimental autoimmune encephalomyelitis (EAE) in a disease model of Multiple Sclerosis (R).

In a nutshell, excess sugar spikes will make your immune system go haywire, making it NOT respond well when it should (ie inadequate detection and protection against infections and cancer cells), while at the same time having it act out (inflammation and autoimmune processes). Not a great combination!

4. Impaired gut health & microbiome

As just mentioned, high sugar consumption is known to reduce the beneficial flora in the gut such as Lactobacillus, and increase autoimmune triggering bacteria, such as Prevotella.

Excessive consumption of dietary sugars has further been shown to reduce the production of short-chain fatty acids in the gut, which can lead to impaired gut barriers (aka ‘leaky gut’) and a less resilient intestinal mucosa and immune system to fight off infections.

All this can contribute to the development of unpleasant gut symptoms such as bloating, food intolerances to normally healthy foods, SIBO (small intestinal bacterial overgrowth), candida overgrowth and more (R).

5. Cellular ageing via advanced glycation end products (AGEs) and free radicals

Advanced glycation end products (short: AGEs) are sugar modifications of proteins and fats that lead to a long-term disruption of cellular function even after blood glucose has normalized. They have been linked to damage of collagen and free radical formation, which causes the tissues to become thickened and stiff, losing their natural elasticity and pliability, contributing to arterial stiffness, increased cardiovascular risk, myofascial stiffness and faster skin aging. This also includes an increased risk for tendinopathies (R) and frozen shoulder (R) which are common (and quite disruptive to quality of life!) concerns in the 40+ category (R, R).

Blood sugar spikes also have been shown to upregulate free radical production and thereby oxidative stress genes, while at the same time downregulating antioxidant genes, making this a double whammy for free radical damage and cellular ageing.

6. Impaired healing and repair

In acute conditions such as surgery and critical illness, insulin resistance and elevated circulating glucose levels have been shown to have a negative impact on patient outcomes via impaired healing and repair (R, R). 

7. Damage to our blood vessels, with an increased risk of hypertension, atherosclerosis and overall cardiovascular disease

There is a close relationship between blood vessel health, its stiffness and blood pressure. Research shows that repeated blood sugar spikes damage the lining of our blood vessels (‘endothelial dysfunction’) much like inflammation does – making it less pliable, thereby increasing blood pressure, increasing arterial calcifications (R), blood clotting (thrombosis risk) (R).

Excessive sugar intake from sugar-sweetened beverages is associated with higher blood pressure levels and hypertension risk, with evidence of a dose-response relationship.

Sugar intake is also associated with enhanced sensitivity to salt’s effects on high blood pressure (R, R, R, R, R, R).

8. Increased levels of ‘bad’ cholesterol (LDL) and lower levels of the ‘good’ type (HDL)

Variations in the size and density distributions of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particles have been related to risk for cardiovascular disease. In particular, increased levels of small, dense LDL particles, together with reduced levels of large HDL and increases in small HDL, have been shown to be integral features of the atherogenic dyslipidemia found in patients with insulin resistance, obesity, and metabolic syndrome.

Increased dietary carbohydrates, particularly simple sugars and starches with high glycemic index, have been shown to increase levels of small, dense LDL (bad!), primarily by mechanisms that involve increasing plasma triglyceride concentrations. Low-carbohydrate diets may have the opposite effects (R). 

A high carbohydrate consumption at the expense of polyunsaturated fatty acids (such as the heart healthy omega 3s) has further been indicated to increase total and LDL cholesterol, but to reduce the protective HDL cholesterol. Regardless of the type of fat being replaced, a high carbohydrate intake promotes an increase in the triglyceride concentration (R, R). 

9. Insulin resistance and metabolic syndrome

Insulin is a hormone that helps shuttle sugar (glucose) into the cells to be used for energy. However, if we continuously overconsume sugars (but in fact also overeat in general), our cells stop listening to insulin, turning them ‘insulin resistant’.

Insulin resistance in itself is linked to the development of Type 2 diabetes, metabolic syndrome, cardiovascular disease, Alzheimer’s and more.

In addition to the cells eventually becoming less responsive to insulin’s signalling, if we are continually exposed to high levels of blood sugar that necessitate insulin to shuttle it into our cells, even acute bouts of high blood sugar have been shown to impair insulin signalling through the generation of free radicals.

However, other factors like chronic low grade inflammation, lack of sleep, cortisol (our stress hormone), a sedentary lifestyle, etc, seem to play a role in the development in insulin resistance also, which we will get another time (R).

AGE accumulation in key metabolically relevant organs has been shown to induce insulin resistance, inflammation, and oxidative stress, which in turn provide substrates for excess AGE formation, thus creating a feed-forward-fuelled pathological loop mediating metabolic dysfunction.

Furthermore, a high consumption of sugar-sweetened beverages increases the risk of obesity and type 2 diabetes mellitus (R). 

1. Polycystic ovarian syndrome and related difficulties conceiving, excess hair growth, acne and more (R).
2. Increased propensity towards hot flashes during (peri)menopause. As estrogen declines, the body’s capacity to handle blood sugar changes, and fluctuations increase the likelihood of those unpleasant hot flashes (R).

The Domino Effect

Are you starting to get the point? Blood sugar spikes don’t just make you hangry or tired—they set off a domino effect throughout your entire body. Inflammation, immune dysfunction, gut dysbiosis, tissue aging, cardiovascular damage, hormonal chaos, and metabolic breakdown. All interconnected. All accelerating each other. But unlike inflammation (which can have hidden, stubborn and somewhat harder to deal with triggers), blood sugar is largely under your direct control. What you eat, when you eat, and how you combine foods makes an immediate difference, in addition to factors like movement and sleep! Hence why optimising your blood sugar is one of the ‘lowest hanging fruits’ – generally a relatively easy fix!

But what does ‘optimal’ blood sugar even look like?

Why the amplitude of your post-meal spikes may matter more than your average blood sugar

A recent study published at the Journal Frontiers of Cardiovascular Medicine shows that the amplitude of a spike may be a more robust determinant of cardiovascular disease risk than average glucose levels (as measured by HbA1c).

The study showed that even for individuals with ‘normal’ blood sugar on average, those in the lowest (69-107 mg/dl = 3.8 – 5.9 mmol/l) vs the highest (150-194 mg/dl = 8.3 – 10.8 mmol/l) range of their post meal blood sugar spike, there was a 27% increased risk of cardiovascular disease in those that had poorer blood sugar control and increased spikes.

Along with the amplitude, the duration outside the ’normal’ range is also likely to be important, ie how long it takes the body to get the blood sugar back into ideal ranges (R).

Another study also showed that repeated administration of hyperglycemic (high blood sugar) spikes robustly increases atherosclerosis, even if their lipid profile and HbA1c (a biomarker usually utilised to define blood sugar averages over the past months) remain unaltered (R)! Average blood sugar (HbA1c) can seemingly be ok, if high blood sugar spikes come hand-in-hand with blood sugar drops, bringing the average back to ‘normal’.

And the important note here is that you don’t have to eat donuts every day and be overweight to have blood sugar issues. In fact, many of my health conscious  and skinny patients deal with the metabolic rollercoaster of sugar spikes and dips that leads to hunger pangs, dizzy spells, fatigue and sleepless nights in the short, and other more serious health concerns in the long run.

Note: With sugar I don’t only mean the white table sugar found in candy and donuts. The body actually converts ALL carbohydrates into sugar inside the body, so all the above also includes rice, potatoes, bread, lentils and bananas. While ‘complex carbs’ (the whole foods variety that includes fiber, such as brown rice) are slower to release their sugar content, and have less of a detrimental impact on blood sugar (also called ‘lower glycemic index’), they still DO contain sugar, and if consumed excessively, and not combined with protein and fats to slow their absorption further, can cause problems.