Download Week 4, 2: Fructose

Week 4, Download 2: Fructose
Although our liver is designed to process small amounts of fructose from fruit sugar and honey (back
when these were rare treats for our hunter gatherer ancestors), now we are overloading the liver with
fructose from all directions, through the unlimited supply of unnatural processed junk foods and
drinks in the typical westernised diet.
The dangers of Fructose consumption:
•
Fructose is processed differently to glucose. Where the body can use glucose as fuel, it stores
fructose in the liver. When fructose reaches the liver, it is converted into triglycerides (fat) and
transported around the body for storage. Fructose is stored in the liver as fat and overtime
contributes to non-alcoholic liver disease.
•
Fructose also blocks the metabolism of glucose in the liver, and the conversion of glucose into
its stored form, called glycogen. This consequently causes high level of glucose in the liver,
requiring a greater demand for insulin production (from the pancreas), and overtime the
muscles of the body become more and more insulin resistance.
Fructose causes high insulin levels, high glucose levels, insulin resistance, higher inflammation
production and visceral fat accumulation (abdominal fat). Visceral fat is the body's way of
storing excessive energy. This fat signals inflammatory markers and causes tissues (muscles
and liver), to respond less to insulin, leading to a greater condition of insulin resistance. And
so the cycle continues!
•
Fructose, when converted into Fructose 1-phosphate, drains the energy source, ATP from the
cells, contributing to the dangerous inflammatory response in the body.
•
Fructose causes premature ageing. Fructose forms the Advanced Glycation End Products
(AGEs) when it attaches itself (without an enzyme) to amino acids and fats. Fructose is much
more reactive to create AGEs than Glucose.
This Glycation process leads to inflammation, the production of the dangerous oxidised LDL
cholesterol and promoting the formation of Atherosclerosis and health conditions including
Alzheimer’s disease, diabetes and liver damage.
•
Fructose plays a role in increasing blood pressure (fructose induced hypertension), blood
cholesterol, uric acid, nitrogen build up and lactate production, through its role on increasing
insulin and therefore weight gain. Uric acid is also a predictor for Cardiovascular Disease and
in high levels, causes the painful condition of gout.
High blood insulin leads to greater visceral fat accumulation (the dangerous and inflammation
causing abdominal fat). This accumulation fat is the body's natural way of storing excess
energy. Higher levels of visceral fat, produces more inflammation and causes the tissues to
respond less to insulin. This is known as Insulin Resistance. In Insulin Resistance, the pancreas
needs to produce more and more Insulin, for the body to respond, and therefore take glucose
into the cells of the body.
The vicious cycle of insulin and visceral fat involves:
Increase in insulin resistance ---> increased insulin production ---> increased amount of
visceral fat and inflammation ---> increased insulin resistance ---> alters metabolic functions
---> non-alcoholic liver disease.
Garry Taubes summed it up well in his informative book ​
Good Calories, Bad Calories ​
“…it is
fructose, not saturated fats, that contribute to high insulin levels and insulin resistance,
promoting adipocyte formation around the liver and midsection, and increasing insulin and
leptin levels, all factors associated with premature ageing.”(2​
Pg. 454)
•
Insulin provides fuel and growth for cancer cells, through its effect on Insulin like Growth
Factor (IGF). IGF is secreted by the liver, tissues and cells throughout the body, working locally
where concentrations are highest. IGF is similar to insulin and can mimic its effects, but not as
well (eg muscles taking up glucose). IGF increases with food availability, leading to tissue
growth. It is therefore an indication of long term food availability.
•
Controversially, high insulin levels (from fructose and glucose consumption) lead to a greater
IGF availability to cells, and therefore can proliferate the growth of cancer cells. High insulin
levels are known to also affect Oestrogen in this way (contributing to oestrogen dominant
symptoms such as heavy and painful menstruation and long term conditions such as breast
cancer). High levels of insulin and IGF play a role of normal cells and benign tumours
developing into malignancies of the breast, prostate, colon, and endometrium.
Garry Taubes explains IGF’s role in cancer “​
The working hypothesis of cancer researchers who
study IGF is not that these molecules initiate cancer, a process that occurs through the
accumulation of genetic errors, but rather, that they accelerate the process by which a cell
becomes cancerous, and then they work to keep the cells alive and multiplying​
(2)…
IGF and insulin can be viewed as providing fuel to the incipient fire of cancerous cells and the
freedom to grow without limit. The critical factor is not that diet changes the nature of the cellsthe mutations that lead to cancer- but that it changes the nurturing of those cells; it changes the
environment into one in which cancerous and precancerous cells can flourish."​
(3 Pg 217)
● When the liver is over burdened with fructose, it’s effectiveness at detoxing and metabolising
hormones is compromised. There is some evidence this liver stress can contribute to
non-alcoholic liver disease. (4)
● Many people will also have difficulty with digesting fructose. Symptoms of fructose
malabsorption include bloating and diarrhea. More on this in later weeks.
● Fructose enhances appetite, through increasing the levels of a hormone called ghrelin. You'll
eat sweets and find yourself just wanting more!