Luanne DeChristopher, MSc, on High Fructose Corn Syrup and Coronary Heart Disease in Black Americans
In this podcast, Luanne DeChristopher, MSc, discusses the association between high fructose corn syrup, excess-free-fructose, and the coronary heart disease mortality disparity between Black and White individuals.
- DeChristopher LR, Auerbach BJ, Tucker KL. High fructose corn syrup, excess-free-fructose, and risk of coronary heart disease among African Americans- the Jackson Heart Study. BMC Nutr. 2020;6(70). doi: /10.1186/s40795-020-00396-x
Luanne DeChristopher, MSc, is an independent researcher in biochemistry, molecular biology, and epidemiology, who focuses her research on the associations of high fructose corn syrup intake and health outcomes.
Leigh Precopio: Hello everyone, and welcome to another installment of Podcasts360, your go‑to resource for medical news and clinical updates. I'm your moderator, Leigh Precopio, with Consultant360 Specialty Network.
Recent decades have shown a significant increase in a Black‑White coronary heart disease mortality disparity. With an approximate 30% increase in 30 years, researchers have looked closely at potential underlying causes that may contribute to the disproportionate impact on mortality among Black Americans.
Here with us today is, Luanne DeChristopher, who is an independent researcher in biochemistry, molecular biology and epidemiology, who focuses her research on the associations of high‑fructose corn syrup intake, and the comorbidities of asthma. In her and her team's latest study, they examine the role of high‑fructose corn syrup on coronary heart disease risk and how high‑fructose corn syrup and accessory fructose may play a role in the Black‑White mortality disparity. Thank you for taking the time to speak with me today. Let's dive into your study.
Research suggests the racial disparity of coronary heart disease between black and white individuals may be due to dietary and environmental factors. Why did you decide to focus your study on the relationship between coronary heart disease disparities, and high‑fructose corn syrup and excess free fructose, specifically?
Luanne DeChristopher: I was drawn to investigate health disparity in coronary heart disease as relates to high‑fructose corn syrup intake because years ago, we learned through a rigorous food elimination diet in my daughter that her chronic asthma and bronchitis were being triggered by intake of high‑fructose corn syrup. When we removed the food from her diet, her symptoms disappeared, and when we reintroduced the food, they re‑emerged. A rigorous food elimination diet is a scientific method of assessing sensitivity to a food. That drove me to pursue research to explain how that could be possible.
That research segued me into research of disparities in heart disease, racial disparities, because an overarching theme in my research is underlying fructose malabsorption. And through my research with asthma, I learned that African Americans have higher prevalence of fructose malabsorption than Hispanics, despite higher consumption, for example, of high‑fructose corn syrup sweetened beverages, so I hypothesize that there may be a link there and that drove me to further investigate.
Leigh Precopio: Your results indicated the Black individuals who consumed high‑fructose corn syrup sweetened drinks had two‑and‑a‑half to three times higher coronary heart disease risk. What is the mechanism between these type of fructose and heart disease?
Luanne DeChristopher: There are two mechanisms. They both are mechanisms that relate to underlying fructose malabsorption, specifically, for individuals who are fructose malabsorbers, when they consume foods and/or beverages where the fructose to glucose ratio is higher than 1:1 then that component of the high‑fructose corn syrup remains resident in their gut.
One of two things can happen, or any combination of two things can happen. That is that unabsorbed fructose interacts with dietary proteins in a chemical reaction known as glycation. That chemical reaction, that glycation forms immunogens that in the case of asthma, they bind asthma mediating receptors in the lungs.
In the case of cardiovascular disease, they are also known to form atherosclerotic plaque. The well‑known term for those immunogens is advanced glycation end products. In the case of gut formed, coined the term extracellular newly identified fructose associated advanced glycation end products. Hence EnFruAGE. That's one hypothesis.
And the second relates to alterations to the microbiome. There is a lot of research underway right now that has focused on the link between disruptions to the microbiome and health.
Researches have determined that when fructose remains resident in the gut, it disrupts the microbiome by way of reducing the diversity of the microorganisms in the gut, that are residence in the gut, and disrupting the metabolites. Thirdly, disrupting the gut endocrine's normal functioning. Disruptions to the microbiome are engaged in homeostasis of blood pressure, of insulin secretion. Disruptions are going to drive potentially insulin insufficiency, and insensitivity. Alterations are also known to have a direct correlation with dyslipidemia. Researchers have found that when they normalize the microbiome that that dramatically reduces the levels of atherosclerotic plaque in the arteries.
Leigh Precopio: Your study notes that the association of coronary heart disease is prevalent in high fructose to glucose ratios, but not with all forms of fructose. Which forms of fructose are associated with the highest rates of heart disease? What other forms of fructose are currently being investigated?
Luanne DeChristopher: Back to the origins of my research, and that is our findings with our daughter. She could consume sucrose, ie table sugar, ie a disaccharide of glucose and fructose, with no effect. It was elimination of high‑fructose corn syrup that ablated her symptoms.
After studying how it could be possible, that led me to the focus on the ratio, and the concept of excess free fructose. Most foods do not have high fructose to glucose ratios, you can probably identify them by way of one or two hands. Apples, pears, watermelons, mangoes have high fructose to glucose ratio, but other than that, most foods have a 1:1 ratio.
When we talk about what forms the fructose, we're talking about the ratio. We're talking about foods where in the ratio, the fructose to glucose ratio was high. Through my research, I also learned that there has been more fructose in the high‑fructose corn syrup than previously thought. The form that's generally recognized as safe is 55:45, but researchers at the Keck School of Medicine have twice commissioned independent labs. They measure levels in soda, popular fruit drinks, and determined that the levels were significantly higher. They were 1.9:1 and 1.5:1, as opposed to the 1.2:1 that is generally recognized as safe.
We're talking about 65:35 and 60:40, which doesn't sound like a big deal, but when you start quantifying the component that is excess free fructose, that you start comparing that to dosages that are known to trigger fructose malabsorption in some people, for example, children are more sensitive. Research tells us that African Americans have higher fructose malabsorption prevalence. It's specifically not an ultra‑form of fructose, but specifically, the ratio of fructose to glucose, and underlying fructose malabsorption that doesn't get triggered when you consume sucrose, or a 1:1 fructose to glucose ratio of sugars, of these monomers.
Leigh Precopio: Besides race, did any other patient characteristics play a role in your results?
Luanne DeChristopher: When we conducted our research with data from the Jackson Heart Study, a large percentage of the participants consumed high‑fructose corn syrup sweetened beverages once a day or more. I think the percentage was around 60%, but a very low percentage had elevated serum triglycerides. That was significant because it reinforced the possibility, or was consistent with the hypothesis, that the association or the increased risk was due to mechanisms in the gut, rather than fructose metabolism associated mechanisms because if it was related to fructose metabolism, you would expect to see higher level of triglycerides, because triglycerides are an end product of fructose metabolism. You would expect to see that elevated. That was a characteristic that jumped out that was consistent with the hypothesis.
The other thing that I want to also mention is that the increased risk borne by consumers that consumed five times a week or more relative seldom, never consumers, those associations that increased risk was independent of potential confounders. What I mean by that is that it was independent of age, socioeconomic status, was independent of smoking history. It was independent of BMI, total energy intake, and independent of blood glucose levels. Independent of type 2 diabetes status, independent of serum triglyceride concentration, independent of LDL cholesterol, and independent of healthy eating index, independent of exercise of physical activity, independent of hypertension, independent of HbA1c, which is also another indirect measurement of blood glucose levels.
That was all significant because the addition of those compounders did not in any way alter the significance of the result.
Leigh Precopio: Knowing that Black patients are at an increased risk of coronary heart disease, what can clinicians do to reduce their patient's risk of heart disease from high‑fructose corn syrup?
Luanne DeChristopher: Well, I would say two things. I'm not a clinician, and so I think that patients need to consult with their doctors. This is the forefront of research, so as someone steeped in it, I would say that you can test for fructose malabsorption status by way of a hydrogen breath test. The gastroenterologist's office may have ready access to such tests.
The other thing is that if that comes back positive is to avoid it, which is hard because it's been ubiquitous in the food supply. Like I said, because of heavy advertising on the part of the Corn Refiners Association, there's a general perception that it's like sugar. That makes it harder and more challenging to wrap your head around this research. But at the end of the day, avoidance, and in the case of heart disease, that's a tough one. In the case of asthma, it was easier because elimination eliminated the symptoms. Certainly, avoidance is one good approach.
Leigh Precopio: What other adverse health effects might Black individuals experience when consuming large amounts of high‑fructose corn syrup?
Luanne DeChristopher: I've conducted research into other outcomes that are all comorbidities. In one study, we investigated associations with chronic bronchitis. Chronic obstructive pulmonary disease has two branches ‑‑ one is emphysema and one is chronic bronchitis. Chronic bronchitis being separate and distinct from smoking‑related emphysema. These are other adverse health effects that may be associated. That was a cross‑sectional study. It investigated associations and increased prevalence, but longitudinal studies are needed.
The other area that we investigated was idiopathic arthritis. Young adult arthritis, non‑wear and tear associated arthritis. We saw the same results, meaning that regular intake of any combination of high‑fructose corn syrup sweetened beverages, including non‑diet soda, fruit drink, and apple juice. I haven't talked about apple juice, and I really should because apple juice is a juice with a 2:1 fructose to glucose ratio. In evaluating or testing the biochemical hypothesis, I use a beverages model to test it. By default, included apple juice, because apple juice, like I said, has a 2:1 fructose to glucose ratio. I'm not sure if I mentioned the other fruit earlier. It's apples, pears, watermelons and mangoes. In our food supply of those fruits, the most significant is apple juice. It's a major contributor of excess free fructose to the American diet. It has been consistently associated with each of the outcomes that we investigated.
To further that point, we also tested associations with orange juice. Orange juice is interesting because it has comparable levels of total fructose. It has comparable levels of post‑pasteurization vitamin C levels as apple juice, and it has a similar or comparable glycaemic load. What distinguishes it from apple juice is excess free fructose profile, meaning its fructose to glucose ratio in orange juice is 1:1. In each of our studies, when we could investigate orange juice, when it was distinguished from other juices, we found either no significance, no association with any of the outcomes that we researched, or it was protective.
Again, further reinforcing the hypothesis that the causal role points to the excess free fructose, the fructose to glucose ratio that is consistent with the proposed mechanism.
Leigh Precopio: What other knowledge gaps exist in this area?
Luanne DeChristopher: I would say that the knowledge gap, that we need to gain momentum, and move the research towards clinical research, so at this point in time, the possibility of the biochemistry has been confirmed, both in terms of glycation in the gut, and in terms of the microbiome and the effects of fructose have been confirmed. We need more research in those areas. But we also need, more importantly, I would say, the clinical study. That will make a huge difference in furthering our knowledge and closing the knowledge gap. We also need to get a better handle on increased awareness of the fact that fructose malabsorption is an underlying condition wherein the symptoms extend beyond bloating, gas, and interference with nutrient absorption, that the consequences are much more far‑reaching than that.
We need to also better understand how much excess free fructose has been in the food supply. There's no place where you could look right now where you could determine average per capita intake of excess free fructose. It has gotten very little attention, like I said earlier, because there has been so much advertising to impart the message that high‑fructose corn syrup is just like sugar, when, in fact, studies have shown consistently that there has been more fructose in high‑fructose corn syrup than is generally recognized as safe.
That research needs to have broader awareness, and that will help drive research into the greater consequences of fructose malabsorption and also widen our understanding of the fact that there has not been a genetic basis identified that explains why some people can more readily absorb unpaired fructose than others. It's just a normal range. It ranges from 5 grams to 50 grams. That's very broad. When you consider natural foods, it has really not been an issue. In other words, my point is that it's a manmade problem, because most natural foods when they're moderately consumed, standard portion sizes, or normal portion sizes, then they're very unlikely to trigger fructose malabsorption. Except perhaps in young children. The problem lies in sweeteners. Sweeteners that have been turned on its head, where the ratios have been ratcheted up, and then the added sweetener is found their way into a broad array of foods and become ubiquitous in the food supply.
In closing, I would say that there's more on the horizon. I'd like to believe that my research has been a catalyst for further research, and my sense is that there is more on the horizon that will be consistent with the results that we've seen thus far. And again my strong hope is that it will gain mindshare with respect to the racial health disparities, and help us to better understand, with increased focus, why there's been a doubling of childhood asthma during the time period where high‑fructose corn syrup became ubiquitous in the food supply.
I hope my research will again, gain mindshare with respect to why African Americans are 30% more likely to die from heart disease, again within the time window associated with the proliferation of high‑fructose corn syrup in the food supply. These trends, these phenomena, occurred within a time window of 1980 to 2010, 2013. My research suggests that the two are correlated and I'm very hopeful that there is further investigation that will help better understand it.
Leigh Precopio: Great. Thank you again for taking the time to answer all my questions today.