Fat, Carbs and Cardiovascular Disease
Wednesday, November 2, 2011
LifeTime WeightLoss in Carbohydrates, Fat, Metabolism, Tom Nikkola, heart health


If you were to ask the average person what causes heart disease, he or she would probably say dietary fat. Though fat has been vindicated through many different studies, it is still common for people to have the impression that dietary fat is unhealthy. We’ve discussed how dietary fat has been unnecessarily vilified for decades in previous articles, such as Saturated Fat: Wrongfully Accused, Cholesterol Gets a Bum Rap, and Myth Busting: Fat. A new research review from The Netherlands Journal of Medicine sheds more light on the confusion surrounding dietary fat, especially saturated fat, carbohydrates and cardiovascular disease. In many ways, Europe tends to be more progressive around nutrition, supplementation and drug therapy. Hopefully a review such as this one will pave the way for similar messages here in the United States in the near future.

Historically, high LDL cholesterol was seen as one of the most significant risk factors for heart disease. In recent years, LDL by itself has been shown to be less significant than once thought. In fact, LDL cholesterol by itself is not a cause of atherosclerosis. Rather, it is a sign that something else is going on in the body which may lead to atherosclerotic plaque. LDL cholesterol can be found in different sizes. Unfortunately, most people do not get their particle size measured when they get lab work done.

Large-particle LDL cholesterol does not affect heart disease risk, whereas high levels of small-particle LDL cholesterol increases risk for heart disease. When you add high levels of small-particle LDL cholesterol to elevated triglycerides and low HDL cholesterol, the combination is called the "deadly lipid triad." As you can imagine, avoiding nutrition and lifestyle habits that promote the deadly lipid triad is a must if you want to keep cardiovascular disease risk at bay.

Fat and Cholesterol Misconceptions

As discussed in the article Saturated Fat: Wrongfully Accused, eating saturated fat has little to do with the cardiovascular disease so common in Western culture. However, today a common recommendation for those with a poor lipid profile is to reduce saturated fat intake and replace it with carbohydrate. As the authors of the review showed, individuals who replace dietary saturated fat with carbohydrate end up with both decreased LDL and HDL cholesterol levels, increased triglyceride levels and no change to the ratio of total cholesterol to HDL cholesterol, suggesting these changes have no impact on heart disease risk. In fact, even though these individuals have lower LDL cholesterol, they end up with more of their LDL cholesterol being the smaller, dense type of LDL cholesterol. So, they have a little less total LDL cholesterol, but the overall result is more small-particle LDL cholesterol, higher triglycerides and lower HDL cholesterol – the “deadly lipid triad.”[i]

What if saturated is replaced with other fats? When 5% of energy from saturated fat is replaced with polyunsaturated fat (olive oil), the result is a meager 7.5% decrease in heart disease risk.i Overall, there appears to be little benefit in these changes to diet.

More recently, omega-3 (fish oil) and omega-6 fats (sunflower oil, corn oil), polyunsaturated fats, have been recommended to reduce heart disease risk. As the authors point out, the benefits of omega-6 fatty acids have been misinterpreted in research. In studies where both omega-3 and omega-6, linoleic acid (like corn oil), are consumed, the health benefits actually come from the omega-3 fatty acids.[ii] When the two fats are reviewed separately, omega-3 fatty acids have a significant effect on reducing heart disease while replacing saturated fat intake with omega-6 actually increases heart disease risk. Next time you see vegetable oil being promoted as healthy, remember this fact. Use some grass-fed butter or coconut oil instead and eat plenty of fatty fish or supplemental fish oil.

If saturated fat doesn't cause cardiovascular disease, what does?

The authors reiterate two potential causes of CVD which are becoming more accepted. First, they discuss the effect chronic, low-grade inflammation has on heart disease risk. Chronic inflammation is seen with insulin resistance, stress and as a result of other factors such as environmental toxins. High blood lipid levels are connected to inflammation as well.

The other potential cause of cardiovascular disease is carbohydrate consumption. Consuming carbohydrates, even when total calorie intake is kept below maintenance levels, stimulates the production of triglycerides in the blood, along with decreasing the particle size of LDL cholesterol.

Studies show eating less carbohydrate and more saturated fat results in lower fatty acid levels in the blood than diets equal in calories, with less saturated fat and more carbohydrate. The lower saturated-fat and higher carbohydrate levels also increase the risk of developing non-alcoholic fatty liver disease, which impacts over a quarter of adults living in Western cultures.

Does this mean individuals should be unconcerned about their saturated fat intake? Not necessarily. When people eat saturated fat AND too much carbohydrate, the two together can put the body in more of an atherogenic state than when reducing one of the other. The consumption of carbohydrate prevents the body from using the saturated fat (or really any fat) for energy, since it stimulates insulin. The carbohydrates also stimulate the production of additional fatty acids from the carbohydrates themselves. The evidence suggests dietary carbohydrate has far more of an impact on cardiovascular disease than saturated fat.

Summary

The tide is changing in how development of cardiovascular disease is seen in relation to diet, though not fast enough. Consumers must become more educated about the truth around heart health as food companies and large organizations will be much slower to change their messaging. To summarize what the evidence suggests about cardiovascular disease,

To reduce the chance of developing cardiovascular disease, instead of eating less saturated fat, the authors of the article suggest:

Recommendations to increase intake of omega-3 PUFA, fruit and vegetables and reduce sodium intake to increase physical activity, to reduce trans-fatty acid intake and reduce the intakes of carbohydrate with high glycemic index, such as notably found in soft drinks and candy, seem more prudent candidates in the battle against CVD than to reduce SAFA intake to the recommended <10% energy, and also because in daily practice saturated fatty acids are mostly replaced by carbohydrate with high glycemic index.ii

Continue the discussion in the comments section below. Post your thoughts and questions.

Written by Tom Nikkola - Director of Nutrition & Weight Management

For another great article on this topic, check out Experience Life Magazine's recent article A Big Fat Mistake


[i] Kuipers RS, de Graaf DJ, Luxwolda MF, et al. Saturated fat, carbohydrates and cardiovascular disease. Net J Med. 2011;69(9)372-378

[ii] Ramsden CE, Hibbeln JR, Majchrzak SF, et al. n-6 fatty acid-specific and mixed polyunsaturated dietary interventions have different effects on CHD risk: a meta-analysis of randomized controlled trials. Br J Nutr. 2010;104:1586-600

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