July 01, 2005
Iron And Cholesterol Increase Cancer Risk
Dr. Arch G. Mainous, III and colleagues at the Medical University of South Carolina in Charleston have found that having a combination of either high VLDL cholesterol or low HDL cholesterol with high iron in the blood raises cancer risk by a factor of 2.68 and 2.82 respectively.
Iron and lipids combine to create oxidative stress, and oxidative stress has a role in the development of cancer. The objective was to determine the risk of cancer among persons who had both elevated iron and lipids. The authors conducted an analysis of the cohort available in the Framingham Offspring Study. Adults aged 30 or more years at baseline had serum iron and high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol, and very low density lipoprotein cholesterol (VLDL-C) assessed in 1979–1982 and were followed for development of cancer until 1996–1997 (n = 3,278). Cox regression models were computed while controlling for age, gender, smoking status, and body mass index. In adjusted models, both elevated iron (hazard ratio (HR) = 1.66, 95% confidence interval (CI): 1.11, 2.46; 29 cases) and VLDL-C (HR = 1.54, 95% CI: 1.04, 2.28; 93 cases) had significant independent risks for development of cancer. When elevated iron was combined with elevated VLDL-C, the adjusted relative risk of cancer increased (HR = 2.68, 95% CI: 1.49, 4.83; 18 cases). Elevated iron and low HDL-C also had a significant adjusted relative risk of cancer (HR = 2.82, 95% CI: 1.50, 5.28; 14 cases). The results suggest that elevated serum iron levels coupled with either high VLDL-C or low HDL-C appear to interact to increase cancer risk in this cohort.
Those are huge increases in risk, almost tripling the best case risk. The high iron is probably generating free radicals that are oxidizing the LDL and VLDL cholesterol. Perhaps the HDL cholesterol removes or neutralizes the reactive forms of LDL and VLDL and hence lower HDL raises the risks.
Exercise will raise HDL cholesterol. What will lower VLDL cholesterol? Same factors that lower LDL cholesterol? Then there is iron. Are the high iron people in this study that way due to genetic factors? In other words, what can be done to lower cancer risk due to cholesterol and iron interactions? Keep in mind as well, the oxidative stress that produces the higher cancer risk also probably accelerates general aging. So anything that reduces cancer risk from cholesterol and iron probably slows down aging in general.
I don't think oxidized cholesterol is the problem. HDL cleans up fat from the bloodstream and other tissues and transports fat to the liver. LDL and VLDL transport fat from the liver into the bloodstream to distribute to other tissues.
I would suggest that oxidized fat causes the increased risk. Elevated LDL and VLDL would tend to increase the amount of fat floating around the bloodstream and other tissues. Lowered HDL would tend to do the same by not cleaning up what's out there as quickly.
If one has elevated iron, show up at the red cross every three months to donate a pint of blood. That'll keep it under control.
Or menstruate once a month or so. That'll clean out some iron straight away.
I would take this study with a huge grain of salt.
Peroxidized/oxidized lipids are toxic to all cells, and interestingly enough, preferentially toxic to cancer cells. There have been serious flirtations with using oxidized lipid fractions as a cancer therapy.
Also the wave of peroxidized lipids that hits every time you excersize is one of the ways your body protects from cancer.
As to iron, it rarely runs around the body unbound, but the association of high iron/high cancer risk has been around a while.
It would be interesting to see a hemoglobin/cancer risk graph.
High iron has also been associated with heart problems. The solution suggested was, as Bob suggested, get off your arse and donate some blood.
I wouldnt neessarily call 2.8 a "huge increase in risk." I'm not sure what age group this applies to, but I have read that a middle aged adult's risk of getting a fatal cancer is 1 in 3000 to 1 in 5000 per year. So 1 in 1500/year is not a "huge increase in risk" but certainly a notable increase.
Given that once you remove lung cancer from the equation the age adjusted death risk of all cancers has been absolutely constant for over 50 years while heart disease has fallen by about 60%, and given that reduced LDL and VLDL and increased HDL have been substantially responsible for this reduction, the idea that cholesterol greatly effects cancer seems unlikely.
I eat lots of pickles and meat and i am wondering if that will increase my chance of cancer or if pickles and meat might help reduce my chance of cancer?
Regarding a two-fold increase in risk as not being a lot, and that a 1 in 1500 chance isn't much more than a 1 in 3000, if you're odds of winning the lottery were EITHER, you saying you wouldn't play? Let's put it this way: if you were on your death bead, scheduled to die in a minute, what would you give to have one more day? Or week? Or Year? The point is, do those things BEFORE you're on your death bed. When you're on your death bed, you don't have anything to negotiate with! When you're healthy, YOU DO!
And regarding giving blood to decrease iron, isn't it the concentration of iron that matters? Sure if you replace that fluid loss with water the concentration of iron would be less, but how long would that last, a few days?
Rearding Mr. Vassar's comments: People are eating more fat, not less. This raises, not lowers, cholesterol. Heart disease has increased, not decreased.
brian, your last part is not entirely correct.
if you charted saturated fat consumption from 1900 - now, people are eating less and less animal fat, due to the constant barrage in media about saturated fats being bad.
heart disease has increased, along with diabetes, mainly due to the refined carbs people have been increasing in their diets. think bagel with fat-free cream, and sugar everywhere - even some whole grain bread. otherwise that whole grain sandwich you're having wouldn't taste as good as it does.
as for the original topic of this post, its most likely not the iron and cholesterol that increase your risk, but whatever's raising your iron and cholesterol is also raising your risk as well. think of all of them as side effects of eating certain foods, not as causes of each other.