<p class="p1"><span class="s1"><a href="https://peterattiamd.com/rickjohnson2/?utm_source=podcast-feed&utm_medium=referral&utm_campaign=220207-pod-rickjohnson&utm_content=220207-pod-rickjohnson-podfeed"> View the Show Notes Page for This Episode</a></span></p> <p class="p1"><span class="s1"><a href="https://peterattiamd.com/subscribe/?utm_source=podcast-feed&utm_medium=referral&utm_campaign=220207-pod-rickjohnson&utm_content=220207-pod-rickjohnson-podfeed"> Become a Member to Receive Exclusive Content</a></span></p> <p class="p2"><strong>Episode Description:</strong></p> <p class="p2">Rick Johnson, Professor of Nephrology at the University of Colorado and a <a href="https://peterattiamd.com/rickjohnson/?utm_source=podcast-feed&utm_medium=referral&utm_campaign=220207-pod-rickjohnson&utm_content=220207-pod-rickjohnson-podfeed"><span class="s2">previous guest</span></a> on The Drive, returns for a follow-up about unique features of fructose metabolism, and how this system that aided the survival of human ancestors has become potentially hazardous based on our culture's dietary norms. In this episode, Rick explains how the body can generate fructose from glucose and how circulating glucose and salt levels can activate this conversion. He discusses the decline in metabolic flexibility associated with aging, as well as how factors such as sugar intake or menopause-associated hormone changes can alter responses to sugar across a lifetime. In addition, Rick lays out strategies for combating the development of metabolic illness using dietary changes and pharmaceutical therapies, and he discusses the impact of fructose metabolism and uric acid on kidney function and blood pressure. He concludes with a discussion of vasopressin, a hormone that facilitates fructose's effects on weight gain and insulin resistance.</p> <p class="p2"><strong>We discuss:</strong></p> <ul class="ul1"> <li class="li2">Unique features of fructose metabolism and why it matters [2:45];</li> <li class="li2">A primer on fructose metabolism and uric acid [10:30];</li> <li class="li2">Endogenous fructose production, the polyol pathway, and the effect of non-fructose sugars [22:00];</li> <li class="li2">Findings from animal studies of glucose and fructose consumption [29:00];</li> <li class="li2">What calorie-controlled studies say about the claim that a "calorie is a calorie" [42:15];</li> <li class="li2">Implications for aging and disease [51:15];</li> <li class="li2">Impact of endogenous fructose production on obesity and metabolic syndrome [1:01:30];</li> <li class="li2">Why vulnerability to the negative effects of sugar increases with age and menopause [1:04:30];</li> <li class="li2">Dietary strategies to reduce the negative impact of fructose [1:16:30];</li> <li class="li2">The role of hypertension in chronic disease and tips for lowering blood pressure [1:30:45];</li> <li class="li2">The impact of fructose and uric acid on kidney function and blood pressure [1:39:45];</li> <li class="li2">The potential role of sodium in hypertension, obesity, and metabolic syndrome [1:49:00];</li> <li class="li2">The role of vasopressin in metabolic disease [1:54:00];</li> <li class="li2">More.</li> </ul> <p class="p1"><span class="s1"><a href="https://peterattiamd.com/newsletter/?utm_source=podcast-feed&utm_medium=referral&utm_campaign=220207-pod-rickjohnson&utm_content=220207-pod-rickjohnson-podfeed"> Sign Up to Receive Peter's Weekly Newsletter</a></span></p> <p class="p2">Connect With Peter on <a href="https://twitter.com/PeterAttiaMD"><span class="s2">Twitter</span></a>, <a href="https://www.instagram.com/peterattiamd/"><span class="s2">Instagram</span></a>, <a href="https://www.facebook.com/peterattiamd/"><span class="s2">Facebook</span></a> and <a href="https://www.youtube.com/channel/UC8kGsMa0LygSX9nkBcBH1Sg"><span class="s2">YouTube</span></a></p>
Actionable Insights
1. Eliminate Sugary Liquid Calories
Immediately get rid of soft drinks and fruit juices, and drink them minimally if at all. Liquid fructose is absorbed very quickly, overwhelming the gut’s protective mechanisms and causing severe ATP depletion in the liver, which drives metabolic syndrome and obesity.
2. Avoid Added Sugars in Foods
Be vigilant about and limit consumption of foods with added sugars, such as sucrose or high fructose corn syrup, which are often found in processed foods like pasta sauce. These added sugars contribute significantly to high fructose intake, driving metabolic derangements.
3. Prioritize Whole Fruits Over Dried/Juiced
Choose natural, whole fruits over dried fruits or fruit juices. Whole fruits contain fiber that slows fructose absorption, and the intestine can shield against small amounts of fructose (around 4-6 grams), reducing ATP depletion, whereas dried fruits are concentrated in fructose and may lack beneficial nutrients.
4. Limit High-Fructose Fruits
Be cautious and limit consumption of fruits known to be very high in fructose, such as figs, dates, and mangoes, as well as apples, pears, and plums (around 9-10 grams of fructose). These higher concentrations can overwhelm the body’s protective mechanisms.
5. Low-Fructose Diet for NAFLD
If diagnosed with non-alcoholic fatty liver disease (NAFLD), implement a low-fructose diet (typically 5-10 grams per day, mainly from vegetables and minimal berries) and eliminate alcohol. This intervention has been shown to improve NAFLD in most people, often independent of significant weight loss.
6. Manage Blood Pressure with Lifestyle
For blood pressure in the range of 135/85 mmHg, prioritize nutritional changes (reducing salt, choosing healthier foods) and exercise before considering medication. Dietary and exercise interventions can effectively lower blood pressure in this range, and there’s no strong evidence that antihypertensive medications provide long-term benefit at these lower levels.
7. Reduce Dietary Salt Intake
Reduce your overall salt intake, as high salt consumption is linked to increased blood pressure and can also activate the polyol pathway. This pathway converts glucose to fructose endogenously, contributing to obesity and insulin resistance, in addition to hypertension.
8. Mind High Glycemic Carbs with Age
Be mindful of high glycemic carbohydrates (e.g., rice, potatoes, bread, chips), especially as you age. As the polyol pathway becomes more activated over time (and by high uric acid), these foods can be converted to fructose endogenously, contributing to weight gain and metabolic syndrome.
9. Maintain Healthy Mitochondria
Engage in regular physical activity and consider a low-fructose or calorically restricted diet to maintain or improve mitochondrial health. Healthy mitochondria are more resistant to the metabolic effects of fructose and oxidative stress, which is crucial for energy production and may slow aging.
10. Increase Water with Salty Foods
When consuming salty foods, drink enough water to prevent a significant rise in blood salt concentration. Maintaining stable blood osmolality can blunt the blood pressure-raising effects of salt and prevent the activation of the polyol pathway that converts glucose to fructose.
11. Understand Fructose Absorption Changes
Recognize that chronic exposure to sugar can increase your body’s efficiency at absorbing and metabolizing fructose. This increased absorption means a larger dose of fructose reaches the liver, potentially leading to more severe ATP depletion and metabolic derangement over time.
12. Monitor Uric Acid Post-Menopause
Be aware of the potential for increased uric acid levels post-menopause and its implications for metabolic health. Falling estrogen levels lead to increased uric acid, which can upregulate fructokinase and the polyol pathway, increasing sensitivity to fructose and the risk of obesity, diabetes, and heart disease.