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December 26, 2010

Integrated Supplements Newsletter A Diet For Long-Term Weight Control And Optimal Health Part 3 - In Defense of Fruit

HeaderPicOct10 Even intelligent researchers and health writers often neglect to mention the unique health–promoting properties of fruit. Though the diet trends of recent decades (including low–carb, “Zone,” and “paleo” diets) have much to offer the nutritional discussion, they have also tended to create an exaggerated and irrational anti–carbohydrate / anti–sugar bias. Whether the stance is explicitly stated or merely implied by these diet philosophies, many devotees have begun to equate fruit with sugar (or, more specifically, fruit with fructose) simply because fruit contains sugar. Such logic, however, is dangerously faulty.

The biological effects of sugar–containing whole foods are usually quite different than those of refined sugar. While an excess of refined sugar may eventually exacerbate nutrient deficiencies and compromise health, consumption of fruit has been repeatedly associated with positive health outcomes in disorders such as heart disease, cancer, and – in some studies – even diabetes. Fruit consumption has also been associated with lower body mass index, and increases in fruit consumption have been found to increase the rate of weight loss. Although such associations from population studies don’t prove that fruit is solely responsible for these effects, controlled studies as well have repeatedly found fruit consumption to reduce or eliminate many of the obesity– and disease–associated biological markers indicative of consuming the modern industrial diet. Numerous fruits, for example, have been shown to reduce inflammation and oxidative stress, regulate blood sugar, enhance glycogen synthesis, improve insulin sensitivity, and curb hunger.

Without industrially–processed foods, whatever sugar our distant ancestors ate was sure to be accompanied by a vast array of nutrients needed for proper sugar metabolism and numerous other aspects of health. To focus solely of fruit’s sugar content, and to ignore the biological significance of the vitamins, minerals, fiber, and thousands of bio–active phenolic chemicals in fruits is a particularly prevalent form of intellectual laziness often found in the realm of nutrition today. To build an optimal diet requires that the complexities of foods such as fruit be more fully understood.

How Did We Get Here?

Fruit is far more than just a source of sugar, but, until fairly recently, we humans never had to give this fact much thought. Analyzing, stressing over, and in fact, even thinking about the long–term health consequences of food are likely to be distinctly modern phenomena. Our distant ancestors (assuming they were lucky enough to avoid famine and steer clear of edibles that were acutely toxic) had no choice but to consume foods with a reasonably balanced array of nutrients. The diet of our more recent ancestors had probably evolved to maximize the health–promoting properties of foods, but dietary practices of the time were so largely steeped in religious and cultural tradition, that the scientific rationale for consuming certain foods, prepared in a certain way, was probably rarely questioned or investigated.

With the advent of the industrial age, however, it became possible, for the first time in history, to consume large amounts of food bereft of important micronutrients. The advent of refined grain, sugar, and seed oils has had a profoundly negative influence on the nutritional composition of industrialized diets, but these foods were introduced into commerce when the study of food composition was still in its infancy. Only in the late 19th and early 20th Centuries did researchers even begin to deduce that components of food besides proteins, fats, carbohydrates, and salts were essential to life. Subsequent research allowed scientists to define and isolate various vitamins, the lack of which was found to cause degeneration, disease, and eventually, death.

With knowledge of essential vitamins and minerals, it’s possible to construct a diet with enough supporting nutrients to counter the occasional use of refined foods. This is why, in small to moderate amounts, refined sugar isn’t particularly harmful. But, it’s important to note that, relative to whole foods, there are countless nutrients (many, no doubt, yet to be discovered) which are lacking from refined foods. Where many of these chemicals exist only in whole foods, it would be naïve to think that we can mimic Nature’s pharmacopeia with fortified foods or vitamin and mineral supplementation. Unique nutrients in fruit, for example, may fundamentally alter human metabolism – including the way in which sugars are metabolized. As refined sugar intake increases, and the intake of whole foods like fruit remains sub–optimal, numerous nutritional shortcomings can become increasingly pronounced.

And yet, the unfounded assumption that refined sugar acts similarly to sugar–containing whole foods permeates our culture. Refined sugar–laden sports drinks can be found on the sidelines of every major collegiate and professional athletic event, and widespread cultural bias has convinced many people that such products represent the optimal form of fluid, carbohydrate, and electrolyte replacement for elite athletes. The long–term effects of these products are conveniently ignored simply because, in the short–term, the sugars they contain can supply for the energy demands of physical activity. Rarely, however, is any mention given to the other nutrients athletes need for energy production (e.g., magnesium, et al), or the fact that use of such drinks may exacerbate deficiencies of such nutrients over time.

Note: Along the same lines, many within the sports and bodybuilding communities consume products made with pure refined glucose (dextrose or digestible maltodextrin) in order to elicit an “insulin spike” and aid the storage of nutrients in muscle. Even high–starch whole foods (e.g. potatoes) contain elements which counter the damage which can be caused by pure glucose. Presumably, athletes consuming refined glucose don’t realize the overall metabolic damage they may be imparting with such a practice.

Similarly, though public health authorities universally advocate fruit and vegetable consumption, “medical” foods administered in hospitals and advocated by doctors for such disorders as cancer, often contain shockingly high amounts of refined sugar (and none of the phytonutrients which are so widely advocated). Of course, when disconnects this blatant are conveniently ignored, economic factors are likely to play a major role. Partly because of their long shelf life, and their ability to be shipped long distances and endure high temperatures without spoilage, refined sugars are, generally, far more profitable than whole sugar–containing foods. The economic incentive thus exists for refined sugars to be used excessively at the expense of whole food ingredients.

But interestingly, the anti–sugar crowd often commits the same fundamental intellectual error: they assume that the effects of refined sugar are similar to those of natural sugar–containing foods.

For example, some nutritionists are fond of informing their clients that orange juice has as much sugar as soft drinks. This advice implies that the two are metabolized similarly – a stance which the research simply doesn’t support. Many “paleo” diet advocates shun fruits, noting that fruit may have been only available seasonally to our distant ancestors, and that modern fruit is likely to be far different (i.e., higher in sugar) than the fruit which was available during the early stages of human evolution. These points may be true, but they don’t change the fact that even widely–available modern fruits (e.g., apples, berries, oranges, orange juice, etc.) have been associated with numerous health benefits and, acutely, positive changes in numerous markers of disease.

Most recently, as the sugar fructose has been the victim of particularly vehement attacks, natural sources of fructose (i.e., fruit) have also been unfairly maligned due to the faulty assumption that fructose exhibits inherent toxicity. As we began to examine in our previous Integrated Supplements Newsletter, the research actually shows, for all practical purposes, that the exact opposite is true – modest doses of fructose, and fruits, are actually associated with health benefits. Clearly, such widespread confusion calls for a far more nuanced understanding of fruit and its components.

Fruit Consumption, Body Mass, and Weight Loss

Many similar phytonutrients are common to both fruits and vegetables. In population–based research, therefore, the effects of fruits and vegetables are often studied together. For this reason, nutritional policymakers often recommend fruits and vegetables as significantly protective components of a healthy diet:

Study Link – Overview of the health benefits of fruit and vegetable consumption for the dietetics professional: selected literature.

Quote from the above study:

Epidemiologic evidence of a protective role for fruits and vegetables in cancer prevention is substantial…Current scientific evidence also suggests a protective role for fruits and vegetables in prevention of coronary heart disease, and evidence is accumulating for a protective role in stroke. In addition, a new scientific base is emerging to support a protective role for fruits and vegetables in prevention of cataract formation, chronic obstructive pulmonary disease, diverticulosis, and possibly, hypertension.

But where fruits universally contain far more sugar than vegetables, it’s reasonable to wonder what the research has to say about fruit consumption independent of vegetable consumption. Does the sugar found in fruit negate or compromise the health–promoting potential of its other nutrients? Does the sugar in fruit lead to weight gain?

From the research that exists, it seems clear that it does not.

Although fruits are a rich source of calories and sugar, much research shows that fruit consumption – despite (or perhaps, because of) its unique sugar content (relative to starch at least) – is associated with reduced body mass index. The following study also found that increases in fruit consumption were associated with increases in weight loss:

Study Link – Effects of fruit consumption on body mass index and weight loss in a sample of overweight and obese dieters enrolled in a weight–loss intervention trial.

Quote from the above study:

…only fruit consumption was associated with body mass index, showing an inverse relation with body weight in cross–sectional and longitudinal analyses (r=–0.27 to –0.44). The relation between fruit consumption and body weight remained significant after controlling for age, gender, physical activity level, and daily macronutrient consumption (DeltaR(2)=0.06–0.13). Further, increases in fruit consumption were associated with subsequent weight loss, controlling for the same covariates (DeltaR(2)=0.05–0.07).

Study Link – The potential association between fruit intake and body weight – a review.

Quote from the above study:

Two of the intervention studies showed that fruit intake reduced body weight, five of the prospective observational studies showed that fruit consumption reduced the risk of developing overweight and obesity, and four of the cross–sectional studies found an inverse association between fruit intake and body weight. Important methodological differences and limitations in the studies make it difficult to compare results. However, the majority of the evidence points towards a possible inverse association between fruit intake and overweight.

Studies have also shown that women consuming higher amounts of whole fruit have a lower risk of developing diabetes:

Study Link – Intake of Fruit, Vegetables, and Fruit Juices and Risk of Diabetes in Women.

Quote from the above study:

An increase of three servings/day in total fruit and vegetable consumption was not associated with development of diabetes (multivariate–adjusted hazard ratio 0.99 [95% CI 0.94–1.05]), whereas the same increase in whole fruit consumption was associated with a lower hazard of diabetes (0.82 [0.72–0.94])…

Whenever population–based studies like the above are cited, those with dissenting views are quick to point out that correlation doesn’t prove causality. In other words, just because fruit eaters are repeatedly found to be leaner, or to suffer less risk of disease, than non–fruit eaters (or people who eat relatively little fruit) doesn’t mean that fruit, per se, caused these effects – fruit eaters may also engage in numerous other activities (such as exercise, or abstinence from other fattening foods) which could contribute as well. Population–based studies often correct for these other influences, but it is true that such studies don’t prove that fruit is necessarily responsible for the outcomes noted. However, in addition to population studies, many controlled studies have investigated the biological effects of fruit consumption. Certain fruits (and fruit juices) have been found to counter the negative metabolic effects associated with consuming the modern industrialized diet. Taken together, the population–based and metabolic studies provide strong evidence in support of fruit consumption in an optimal diet.

The Biological Effects of Fruit Components

Health writers and nutritionists often warn against the consumption of refined foods. This stance is certainly reasonable considering the strong association between the industrialization of our food supply and the development of the modern epidemics of degenerative disease and obesity. But merely advising against refined foods is the sort of over–simplified blanket statement that can lead to confusion and, ultimately, some strange and misguided dietary practices.

There’s sometimes a tendency, for example, to assume that processing or refining per se imparts negative effects. This is sometimes true, but not always. Cooking is a form of processing which often serves to inactivate dietary toxins which would otherwise prove harmful. The desire to consume unrefined foods, and failure to grasp the benefits of certain types of processing, has lead to such phenomenon as the “raw food” movement in recent years.

Similarly, with regard to sugars, there are those who have begun to obsess over certain ingredients in the food supply, while losing the larger perspective of overall nutritional composition. The trend of choosing products made with cane sugar instead of high–fructose corn syrup (even though both are roughly equal mixtures of glucose and fructose, and both are similarly lacking in nutritional substance) is one such example. Clearly, it’s important to specifically define what types of processing are harmful and, most importantly, why.

Unlike traditional cooking methods, industrial processing of food often allows us to consume calories without the micronutrients needed to put these calories to good use. A lack of magnesium, for example, is probably one of the fundamental reasons why refined sugars (and refined grains) may ultimately have a negative impact on health. In many instances, the negative effects of sugar have been completely negated when additional magnesium was added to the diet.

As we saw in previous Integrated Supplements Newsletters, the sort of exaggerated fructose feeding used in animal studies doesn’t often have much relevance for real–world human intake of fructose. But even with excessive fructose feeding, numerous studies show that the addition of magnesium is able to prevent much, if not all, of the metabolic disruption caused by fructose consumption in laboratory animals:

Study Link – Dietary magnesium prevents fructose–induced insulin insensitivity in rats.

Quote from the above study:

These results suggest that magnesium deficiency and not fructose ingestion per se leads to insulin insensitivity in skeletal muscle and changes in blood pressure.

Study Link – Increased magnesium intake prevents hyperlipidemia and insulin resistance and reduces lipid peroxidation in fructose–fed rats.

Quote from the above study:

Increased magnesium intake improved insulin sensitivity, hyperglycemia, hyperlipidemia and reduced lipid peroxidation in fructose–fed rats.

With this knowledge we can see that the modern rally cries against sugar and fructose are a bit misguided. Merely cutting out sugar won’t necessarily rectify a magnesium (or any other nutrient) deficiency. Rather than treat sugar as inherently toxic, it’s far more meaningful to simply investigate the accessory nutrients needed for proper sugar metabolism. Not surprisingly, these substances will universally be found in fruit.

In addition to vitamins and minerals, fruit is a source of unique dietary fibers. These fibers have been shown to reduce appetite and impart numerous health benefits. In an investigation of the satiety induced by various foods, fruits were among the most filling due to their soluble fiber (and water) content:

Study Link – A satiety index of common foods.

Quote from the above study:

Protein, fibre, and water contents of the test foods correlated positively with [satiety index] scores.

Fruit’s fibers however, have far more important benefits than just filling us up – they may positively impact gastrointestinal and overall health. For example, whether or not all types of dietary fiber play a role in the prevention of colorectal cancer is controversial, but studies have found that the soluble fibers in fruits may be uniquely beneficial in this regard:

Study Link – Fiber from Fruit and Colorectal Neoplasia.

Quote from the above study:

When investigating source of fiber within the prospective studies and the two recent large observational studies, modest inverse associations are found for fruit fiber in some of the studies… these modest yet suggestive associations for fruit fiber may provide some insight into the etiologic role of fiber source and composition in colorectal carcinogenesis.

This is because, unlike most insoluble fibers (e.g., the type of fibers often found largely in bran and cereal fiber), many of the soluble fibers in fruit may be imparting prebiotic effects (i.e., they may be acting as a selective growth medium for beneficial strains of human intestinal bacteria). It’s known that bananas, for example, contain a notably high amount of prebiotic fructans – chains of fructose which are indigestible to humans, but which act as a selective fuel source for beneficial intestinal bacteria. When tested, other fruits as well have been shown to contain prebiotic components:

Study Link – In vitro and in vivo evaluation of the prebiotic activity of water–soluble blueberry extracts.

By beneficially altering the intestinal flora, prebiotics have great therapeutic potential in numerous metabolic disease states. As relates to obesity in particular, recent research has shown significant differences in the intestinal flora between lean and obese individuals. Even more interesting is the fact that as obese individuals lost weight, their intestinal flora changed to a healthier one characteristic of lean individuals.

Study Link – Microbial ecology: human gut microbes associated with obesity.

Quote from the above study:

Two groups of beneficial bacteria are dominant in the human gut, the Bacteroidetes and the Firmicutes. Here we show that the relative proportion of Bacteroidetes is decreased in obese people by comparison with lean people, and that this proportion increases with weight loss on two types of low–calorie diet. Our findings indicate that obesity has a microbial component, which might have potential therapeutic implications.

Related research has shown that the inflammation and insulin resistance found in obesity and diabetes may be caused by a pathological intestinal bacterial composition which damages the intestinal lining. The resultant “leaky gut” allows inflammatory bacteria from the intestines (i.e., endotoxin) into systemic circulation, resulting in a chronic low–level inflammatory state known as endotoxemia. This chronic, mildly toxic burden leads directly to systemic inflammation, liver dysfunction, insulin resistance, and increased fat storage:

Study Link – Changes in gut microbiota control metabolic endotoxemia–induced inflammation in high–fat diet–induced obesity and diabetes in mice.

Quote from the above study:

This new finding demonstrates that changes in gut microbiota controls metabolic endotoxemia, inflammation, and associated disorders by a mechanism that could increase intestinal permeability. It would thus be useful to develop strategies for changing gut microbiota to control, intestinal permeability, metabolic endotoxemia, and associated disorders.

Diabetics and obese individuals have been shown to have notably high amounts of inflammatory endotoxin in their blood, and human research has shown that meals rich in fruit and fiber help to prevent the sort of inflammatory response which is associated with endotoxemia and insulin resistance:

Study Link – Increase in Plasma Endotoxin Concentrations and the Expression of Toll–Like Receptors and Suppressor of Cytokine Signaling–3 in Mononuclear Cells After a High–Fat, High–Carbohydrate Meal. Implications for insulin resistance.

Quote from the above study:

[High–fat, high–carbohydrate] meal intake induced an increase in plasma [lipopolysaccharide] concentration and the expression of SOCS–3, TLR2, and TLR4 protein, reactive oxygen species generation, and nuclear factor– κ B binding activity (P < 0.05 for all). These increases were totally absent after the AHA meal rich in fiber and fruit.

Phenolics in Fruit – Powerful Anti–inflammatory Agents

The anti–inflammatory effects of fruit are likely to be due to more than just its prebiotic fiber content. A dizzying array of bio–active phenolic compounds have been shown to exibit similar anti–inflammatory effects. Both whole fruit and fruit juice (which is likely to be lacking significant fiber content) have both been shown to counter the inflammatory response associated with modern meals:

Study Link – Postprandial metabolic events and fruit–derived phenolics: a review of the science.

Quote from the above study:

…the collected data suggest that consuming phenolic–rich fruits increases the antioxidant capacity of the blood, and when they are consumed with high fat and carbohydrate ‘pro–oxidant and pro–inflammatory’ meals, they may counterbalance their negative effects. Given the content and availability of fat and carbohydrate in the Western diet, regular consumption of phenolic–rich foods, particularly in conjunction with meals, appears to be a prudent strategy to maintain oxidative balance and health.

With particular relevance to the role of endotoxin in triggering systemic inflammation, insulin resistance, diabetes, and obesity; orange juice has been shown to prevent the increase in toll–like–receptor expression and plasma endotoxin induced by a high–fat, high carbohydrate meal:

Study Link – Orange juice neutralizes the proinflammatory effect of a high–fat, high–carbohydrate meal and prevents endotoxin increase and Toll–like receptor expression.

Quote from the above study:

The combination of glucose or water and the [high–fat, high–carbohydrate] meal induced oxidative and inflammatory stress and an increase in [Toll–like receptor] expression and plasma endotoxin concentrations. In contrast, orange juice intake with the [high–fat, high–carbohydrate] meal prevented meal–induced oxidative and inflammatory stress, including the increase in endotoxin and [Toll–like receptor] expression. These observations may help explain the mechanisms underlying postprandial oxidative stress and inflammation, pathogenesis of insulin resistance, and atherosclerosis.

The following study found that the ingestion of 75 grams of glucose was associated with an increase in reactive oxygen species (i.e., free radicals) as well as the inflammatory marker nuclear factor–kappa B. Orange juice, however, suppressed this effect (as did fructose – further evidence, as we saw in the previous integrated Supplements Newsletter, that glucose and starch are metabolically problematic in the absence of fructose).

Study Link – Orange Juice or Fructose Intake Does Not Induce Oxidative and Inflammatory Response.

Quote from the above study:

Citrus juices, especially orange juice, have been recommended by several health and nutrition groups as a healthy source of calories, and their intake is associated with improved lipid profile and a reduced risk of cardiovascular disease. Furthermore, orange juice is a rich source of flavonoids and vitamin C, which may suppress [reactive oxygen species] generation and inflammatory processes. It is also possible that flavonoids contained in orange juice may reduce or prevent oxidative stress and inflammation induced by macronutrients like glucose, fructose, and sucrose contained in it.

Daily orange juice consumption has also been shown to raise levels of the “good” HDL cholesterol in those with high cholesterol:

Study Link – HDL –cholesterol–raising effect of orange juice in subjects with hypercholesterolemia.

Quote from the above study:

Orange juice (750 mL/d) improved blood lipid profiles in hypercholesterolemic subjects, confirming recommendations to consume >5–10 servings of fruit and vegetables daily.

And similarly, concurrent strawberry consumption has been shown to lower the levels of triglycerides and oxidized cholesterol which are elevated in response to a high–fat meal:

Study Link – Strawberry Modulates LDL Oxidation and Postprandial Lipemia in Response to High–Fat Meal in Overweight Hyperlipidemic Men and Women.

Quote from the above study:

After the [high–fat meal] during the run–in period, [triglycerides] and [Oxidized LDL ] were lower after [a freeze–dried strawberry drink] than [a placebo drink] (p = 0.005, p = 0.01, and p = 0.0008, respectively). [high–fat meal] responses after 6 weeks of [strawberry] versus [placebo] resulted in decreased lipid levels and a sex by treatment interaction for [Oxidized LDL ] (p = < 0.0001, and p = 0.0002). Conclusion: The present results support a role for strawberry in mitigating fed–state oxidative stressors that may contribute to atherogenesis.

Specific Therapeutic Phenolics in Fruit

Digging a bit deeper into the phenolic components of certain fruits, we can see more reasons why fruit consumption is so widely associated with health and metabolic benefits. One of the phenolic components of many fruits, for example, is salicylic acid. The anti–inflammatory and wide–ranging biological effects of salicylic acid are hinted at by the effects its chemical cousin acetyl–salicylic acid, or, aspirin.

In fact, researchers have found that vegetarians and people who eat the most fruits and vegetables have levels of salicylic acid in their blood comparable to those taking low–dose aspirin. These researchers have proposed that the anti–inflammatory and overall health effects of fruits and vegetables may, in part, be attributable to their salicylic acid content.

Study Link – Salicylic acid in the serum of subjects not taking aspirin. Comparison of salicylic acid concentrations in the serum of vegetarians, non–vegetarians, and patients taking low dose aspirin.

Quote from the above study:

Salicylic acid, a non–steroidal anti–inflammatory drug, is present in fruits and vegetables and is found in higher concentrations in vegetarians than non–vegetarians. This suggests that a diet rich in fruits and vegetables contributes to the presence of salicylic acid in vivo. There is overlap between the serum concentrations of salicylic acid in vegetarians and patients taking aspirin, 75 mg daily. These findings may explain, in part, the health promoting effects of dietary fruits and vegetables.

Study Link – Circulating salicylic acid is related to fruit and vegetable consumption in healthy subjects.

Quote from the above study:

This study proved that, after overnight fast, human subjects not taking aspirin display circulating [salicylic acid] in amounts related to [fruit and vegetable] consumption. It is therefore possible that the beneficial effects of regular [fruit and vegetable] consumption in man could also depend on low chronic [salicylic acid] exposure.

Certain inflammatory chemicals produced from omega–6 fatty acids can profoundly impact all aspects of metabolism. This is one reason why an excess of omega–6 fats (i.e., many seed oils) as found in the modern diet, may produce a particularly pathological inflammatory milieu in the human body. The anti–inflammatory effect exhibited by salicylates is, at least in part, due to their ability to inhibit the COX –2 enzyme – the enzyme which catalyzes the production of these inflammatory chemicals in response to stress.

Animal studies have shown that COX –2 signaling is necessary for obesity–linked insulin resistance and fatty liver. Substances which blocked COX –2 function were able to reduce the development of fatty liver and insulin resistance:

Study Link – COX –2–mediated inflammation in fat is crucial for obesity–linked insulin resistance and fatty liver.

Quote from the above study:

Our findings suggest that COX –2 activation in fat inflammation is important in the development of insulin resistance and fatty liver in high fat induced obese rats.

Similarly, in man, aspirin, itself, has been found to reduce lipid–induced insulin resistance via similar mechanisms:

Study Link – Acetylsalicylic Acid Improves Lipid–Induced Insulin Resistance in Healthy Men.

Quote from the above study:

[Acetylsalicylic acid] pretreatment attenuated lipid–induced insulin resistance in healthy humans.

Analysis has found that most fruits contain considerable amounts of salicylic acid, and some of the highest levels occur in berries, and dried fruits:

Study Link – Salicylates in foods.

Quote from the above study:

We found that most fruits contained considerable amounts of salicylate. Raisins and prunes had the highest amounts. Most berry fruits are significant sources of salicylate, with a range from 0.76 mg/l00 gm for mulberries to 4.4 mg/100 gm for raspberries. Apples showed considerable variation of salicylate content between varieties.

Another important (yet largely unrecognized) phenolic component of some fruits is chlorogenic acid. Belonging to a class of phenolics known as hydroxycinnamic acids, chlorogenic acid and similar compounds may have unique benefits in relation to diabetes, liver disorders, and obesity.

Conceptually, it’s helpful to think of type–2 diabetes as an exaggerated stress response. In diabetes, largely because of insulin resistance (i.e., the inability of the body to respond properly to insulin), it’s as if the body is sensing starvation despite the presence of elevated blood glucose. Among other effects, the stress response this elicits causes cortisol to be chronically elevated and liver glycogen to be continually released into the bloodstream as glucose. Glycogen release by the liver is the reason why many low–carbohydrate or low–glycemic foods (or any stress) can still cause significant elevations in blood glucose. We’ve already seen how anything which fosters pathogenic bacteria in the intestines (or similarly, anything which compromises gastrointestinal integrity) can lead to inflammation and endotoxemia – a major contributor to insulin resistance and elevated blood sugar.

Chlorogenic acid has repeatedly been shown to exert remarkably protective effects against liver injury and diabetes, and this effect is likely mediated by chlorogenic acid’s ability to reduce inflammation caused by intestinal bacterial toxins (such as lipopolysaccharide in the following study):

Study Link – Protective effects of chlorogenic acid on acute hepatotoxicity induced by lipopolysaccharide in mice.

Quote from the above study:

Our data suggest that [chlorogenic acid] has remarkable hepatoprotective effects on LPS–induced liver injury and that the possible mechanism is related to its anti–inflammatory action.

The liver is the first line of defense against the bacterial toxins absorbed from the gastrointestinal tract, so it’s not surprising to find that intestinal bacterial toxins place notable stress on the liver. Again, this stress response manifests, in part, by the release of liver glycogen into the bloodstream as glucose. This phenomenon is particularly prevalent in diabetes, and allowing diabetics to store and release liver glycogen appropriately represents a major therapeutic target of diabetes treatment. As chlorogenic acid is able to inhibit the inflammatory effects of the bacteria which set this process in motion, we also find that chlorogenic acid is able to inhibit the enzymes which trigger the release of liver glycogen:

Study Link – Chlorogenic Acid and Synthetic Chlorogenic Acid Derivatives:  Novel Inhibitors of Hepatic Glucose–6–phosphate Translocase.

In real–world situations, food sources of chlorogenic acid (and related compounds) have been shown to be remarkably protective against diabetes. It’s thought that the chlorogenic acid content of coffee, for example, is largely responsible for the beverage’s beneficial effects with regard to glucose regulation, insulin resistance, and the development of diabetes:

Study Link – Coffee, glucose homeostasis, and insulin resistance: physiological mechanisms and mediators.

Quote from the above study:

Epidemiological studies show coffee consumption to be correlated to large risk reductions in the prevalence of type 2 diabetes (T2D). Such correlations are seen with decaffeinated and caffeinated coffee, and occur regardless of gender, method of brewing, or geography.

Coffee berries (i.e., the fruit as well as the coffee bean) are a source of chlorogenic acid as are many other fruits:

Study Link – Polyphenols: food sources and bioavailability.

Quote from the above study:

Caffeic and quinic acid combine to form chlorogenic acid, which is found in many types of fruit and in high concentrations in coffee: a single cup may contain 70–350 mg chlorogenic acid. The types of fruit having the highest content (blueberries, kiwis, plums, cherries, apples) contain 0.5–2 g hydroxycinnamic acids/kg fresh wt.

Interestingly, the chlorogenic acid content of dried plums (i.e., prunes) is greater than that of fresh plums. Many people associate the mild laxative–like effect of prunes (and coffee) to fiber, but it’s more likely their chlorogenic acid content which is responsible. Chlorogenic acid is known to act as a cholagogue, a substance which stimulates bile flow. Bile stimulates intestinal peristalsis and softens stool. Oftentimes, when increased fiber intake worsens constipation, the ingestion of chlorogenic acid–containing foods rectifies the problem by stimulating bile flow.

Also, in addition to altering the intestinal bacterial composition via prebiotics, stimulating bile secretion and bowel function with chlorogenic acid is another way to reduce the burden of endotoxin stress by helping to ensure regularity.

Salicylic acid and chlorogenic acid are just two of the thousands of phenolic compounds known to exist in fruits. Although the beneficial actions of these two organic acids are significant, there are sure to be many more compounds in whole foods with additional health–promoting properties. Numerous other compounds in fruits, for example, have exhibited anti–oxidant, iron–chelating, and hormone–regulating action. Though the properties of these chemicals haven’t been fully explored, the assumption that the metabolic effects of fruit can be reduced to the metabolic effects of sugar can already be regarded as embarrassingly simplistic.

In all, the scientific evidence provides strong support for the role of fruit in any healthy diet – especially diets geared towards weight loss. Despite the current trend of anti–sugar and anti–fructose alarmism, the role of sugar in obesity and metabolic disorders isn’t quite what some health writers believe it is. Rather than sugar imparting inherent toxicity, certain amounts of sugar (the majority of which coming from whole foods such as fruit) seem to be preferable to none at all. In addition, often–ignored components of fruit are likely to impart numerous health benefits. With this perspective on sugar metabolism and blood glucose regulation, in the next edition of the Integrated Supplements Newsletter, we’ll examine how, rather than sugars, some uniquely modern dietary fats are likely to be largely responsible for causing the types of metabolic disruption associated with obesity and related disorders such as diabetes.


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