In his 2023 Wellness Academy Q&A, Gerardo Mackenzie, PhD, offers a wealth of knowledge on personalized nutrition, wellness, and lifestyle. Tackling questions on topics ranging from genetic testing to dietary adjustments and mindfulness, Dr. Mackenzie provides practical advice and scientific insights to empower individuals in their journey toward better health.
About the expert: Gerardo Mackenzie, PhD
Gerardo Mackenzie, PhD, is an Associate Professor and Co-Vice Chair in the Department of Nutrition at UC Davis, where he also serves as an Associate Nutritionist in the Agricultural Experiment Station (AES). With a Ph.D. in Cell Biology and a B.S./M.S. in Biochemistry from the University of Buenos Aires, Argentina, Dr. Mackenzie brings a wealth of knowledge and expertise to his role. His research focuses on the role of diet and lifestyle factors in cancer development, prevention, and treatment. Key research projects include understanding the cellular and molecular mechanisms linking obesity, inflammation, and cancer, evaluating the impact of dietary interventions such as the ketogenic diet alongside standard chemotherapy for pancreatic cancer, and investigating the potential of select nutraceuticals as chemopreventive agents.
Q&A with Gerardo Mackenzie, PhD
This transcript has been edited for clarity.
Q: What about all the testing that’s available right now? Are there tests we should be considering, such as lab tests or genetic markers, to understand our vulnerabilities?
Dr. Mackenzie: Well, regarding cancer prevention, there are some markers that could be detected. For example, if one carries the BRCA2 genes.
Those could be discussed with a healthcare professional and asses if it makes sense. As these tests and technologies get cheaper and more available for clinics and hospitals, it makes sense as we move forward to personalize nutrition and personalize medicine to help us understand our personal risk.
Again, genetics play a huge role in the course of many diseases. So as we can understand more, I think it would be beneficial to consider.
Q: Could you explain what personalized nutrition means? How can it guide us in finding the right diet and supplements?
Dr. Mackenzie: Yes, again, it goes hand in hand with personalized medicine which is individualized towards our personal needs. And just as it was discussed also in the previous talk about exercises like what we would need to achieve our goals.
For example, if I am middle age, I would look to see how I can support my healthy with a healthy nutrient intake with a health diet. But my mother, who is over 70, would need to supplement more specifically for something like calcium. Or my wife maybe needs a different intake.
You should take into account specific goals, and not just to prevent but maybe to achieve our health goals, and that is more related to personalized nutrition. As technology advances and we are able to get a lot of specific testing, we shouldn’t just go into the general guidelines, but move them towards our personal needs.
Q: What about supplements? Most people take them without knowing what they’re supplementing for. What’s your advice on that?
Dr. Mackenzie: That’s a great question. And again, it’s also personalized. And it depends on the age and the goal of the person, and if they are already getting what they need from the diet they are consuming.
We should always be adapting, and it can be difficult to know at what age or which supplement we should be adjusting. So having clinical markers for us when we are deficient in something or sufficient, this could help us know to supplement if needed for the deficiency. But most of us probably get sufficient nutrients from our diet and many of the foods we already eat.
So personally, I do not recommend a supplement if we don’t really need it, but in specific cases this is a conversation to discuss with your health care provider. We should monitor our health needs constantly, and then adapt based on those needs.
Q: It sounds like what you’re recommending is people should start with a good diet before we supplement. Would you also say it’s looking at all those other aspects as well, like being active? For example, the saying you can’t supplement a bad diet or not being active?
Dr. Mackenzie: Yeah, it goes hand in hand. The healthy diet plus the physical activity, and our social and mental health. It all goes together. Having those pieces and making steps towards achieving our goals or changing things up will help.
Q: Is there really an “anti-cancer diet,” or is it just about eating well?
Dr. Mackenzie: There is no specific anti-cancer diet. But I think its about having different changes towards the recommendations I mentioned in the presentation.
And it’s very difficult for everyone to achieve all of the recommendations. For example, I am Argentinian, I love my steak. I like barbecue. So for me it’s very difficult to limit my red meat, like the recommendations suggest. Maybe I can try to have it every two weeks or reduce it.
So for the recommendations you have to look at what’s achievable for you.
Q: So it sounds like you are advocating for moderation, but what about those who financially just don’t have the means to consume a high quality diet? What advice do you have for those people?
Dr. Mackenzie: Of course, it can be difficult if fruits and vegetables are expensive compared to processed foods. That is always something to discuss. But there is work being done to address this, for example some food banks now instead of offering packaged food they offer more personalized choices where they can choose fruits and vegetables vs more refined carbohydrates.
On a personal level, if you are on a budget, maybe you choose a bread with more fiber, or just get water and not soda. So again, it’s small steps, and of course it’s difficult because it is a complex problem, te financial cost of healthy food. But as we know more, I think small changes can make a big difference.
We talked about social determinants of health, but there are social determinants of wellness as well and this is really one of them.
Q: The next question is from someone who asks about different types of diets, i.e. anti-inflammatory, gluten free diet, whole-foods plant based etc. How can people determine the best diet for their individual needs? Is it just trial and error?
Dr. Mackenzie: I think the simple choice is something that again, is culturally appropriate for you, but you try it and if it’s working then great. Trial and error is the easiest way to go to move forward.
Because I get it, someone can tell me I should eat this and that, but if I don’t know how to cook, I don’t like it, or I don’t see myself eating that way continuously, it’s going to be very difficult for compliance. So I would say go back to the smaller steps and just try.
For example, probiotics are good, and there is evidence showing that a healthy microbiome can help protect us from disease or help with cancer prevention. So maybe you try it, and have measurements along the way to make sure its going the right way.
Q: There’s been a lot of interest in visceral fat as a health risk, even for people who aren’t overweight. What’s your advice for managing it?
Dr. Mackenzie: Again, this is important, maintaining a healthy weight and something that is appropriate for you. Like if you feel good and you can do some exercise then that’s going to be fine and consider what is appropriate in terms of belly fat.
There is some evidence that visceral fat, the fat surrounding the organs, may influence the development of certain gastrointestinal types of cancer. So there is a connection there that we have to be aware of.
Q: A person mentioned they don’t like beans. Are there substitutes that provide similar nutritional benefits?
Dr. Mackenzie: Of course, you shouldn’t eat things you don’t like. So I would look towards other colorful vegetables, maybe try lentils in stead of just beans. Or something like tofu.
Q: What do you think about turkey bacon without nitrates?
Dr. Mackenzie: It’s better than the bacon with nitrates, but again, as we discussed earlier, it may be ok in moderation. For example I eat barbecue in moderation, maybe once in a while its fine. If it’s something that you like to eat and of course it provides some, important nutrients then that’s fine.
Q: What do you think about the non-sugar sweeteners, stevia and some of the other artificial sweeteners that we consume? And how does that play into, you know, our propensity to disease?
Dr. Mackenzie: Yeah, the field is still developing on our understanding of these. There is no clear option, I would say if you prefer sweet things and you prefer not to add straight sugar, than that’s ok.
But this field is still young, and we need longer and more robust studies to provide a definitive answer on what the effects are of chronic consumption of these artificial sweeteners.
Q: Can you say something about the health benefits of fermented food and why they might be of benefit?
Dr. Mackenzie: Yeah again, I like them and I think they are beneficial. Having a healthy gut microbiome has been shown to have beneficial effects against weight control as well as cancer prevention.
There are things like the gut-pancreas-axis and the gut-brain-axis that can be influenced by the gut microbiome. I am in favor of fermented foods.
Q: What about people who go to the other extreme vegan diets and they need to get protein, and, and support their bodies. Is there any evidence that those are better for preventing disease? And how do you supplement the deficiencies that might come to those with, with, you know, vegan diets?
Dr. Mackenzie: Again, I think there are plenty of vegetable protein sources, like from tofu and beans, and you could get enough protein with a balanced diet. That would be fine.
Just like we think about red meat being a good source of iron, there are some vegetable sources that are also rich in iron like spinach and pumpkin seeds for example. Even beans have iron, so you can include those in a vegetarian or vegan diet.
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