Richard Mattes, MPH, PhD, RD

Interview with Richard Mattes, Ph.D., Distinguished Professor of Nutrition Science at Purdue University, Adjunct Associate Professor of Medicine at the Indiana University School of Medicine, Affiliated Scientist at the Monell Chemical Senses Center, and Vice-President Elect for the American Society for Nutrition.

Dr. Mattes received his Ph.D. in Human Nutrition from Cornell University and conducted post-doctoral studies at the Memorial Sloan-Kettering Cancer Center and the Monell Chemical Senses Center. He remained at Monell for 13 years progressing to full member. At Purdue University, Dr. Mattes is the Director of the Ingestive Behavior Research Center, and the Director of Purdue’s Public Health Graduate Program. He also holds numerous external responsibilities including Associate Editor for The American Journal of Clinical Nutrition. He is also secretary of the Rose Marie Pangborn Sensory Science Scholarship Fund. Richard Mattes has been the principal investigator on National Institutes of Health grants continuously since 1984, and has authored of over 265 publications.

 

1. How did you first get involved in nutritional biochemistry and research? What made you interested in the field of nutrition science?

My original plan was to pursue a career in public health. I selected nutrition as a focus because while diet-related disorders were widespread, a large proportion appeared solvable. It was a field where one could make a difference. Following completion of my public health training, I realized I needed a deeper understanding of nutrition science to be in a position to address the issues that now seemed much more complicated. My pivot to nutrition and sensory science stemmed from my work under Shiriki Kumanyika who was interested in sodium intake and hypertension at the time as well as a recommendation by a friend to attend an illuminating course taught by Bruce Halpern, a sensory scientist in the Psychology Department at Cornell. Understanding the drivers of food choice, such as sensory function, seemed to be a critical control point for moderating diet-related chronic diseases.

2. When and why did you first join ASN? What convinced you to join the organization

I joined the American Institute of Nutrition (AIN) in 1986, immediately following completion of my post-doctoral training, when I thought I had completed a sufficient body of work to be eligible for membership. I considered it an honor to be a member of a professional association that included many of the scientists publishing work that guided my thinking. It was also an important resource for me since I was at an institution with a mission to understand the mechanisms and functions of the chemical senses, not address nutrition problems. So, while I had wonderful colleagues, few had similar training to me or similar interests and as a young scientist, I needed more feedback from people knowledgeable in nutrition. The AIN was an invaluable resource.

3. What aspects of ASN membership have you found most useful, professionally? What other aspects of your membership do you find useful as your career has progressed?

Membership benefits like access to all four ASN Journals have been, and continue to be the primary means for my keeping current with the advancing science.

4. What aspects of your research do you foresee being most important for ASN members?

My research has always been at the interface between nutrition, sensory, food and psychological sciences. I hope that it serves as a bridge to these other areas as they are integral to understanding food choice and how behavior influences physiology.

5. Can you tell us more about your current position and the research activities in which you are involved?

I currently have a split appointment. Sixty percent of my effort is devoted to building and administering a new public health graduate program. So, after over thirty years of basic and clinical research, I find myself back at my original professional aspiration. The other forty percent of my effort is as a traditional faculty member, though I do direct the Ingestive Behavior Research Center which provides a unique opportunity to train doctoral students in this area of specialization.

6. What do you feel are the biggest challenges facing nutrition researchers today? Are there any areas where you would like to see more research?

My biggest concern stems from the decreasing funding base for nutrition research. Of course, it directly limits what science can be pursued, but more insidiously, I think it drives scientists to take more advocacy roles for their area of work and this corrodes the scientific process. It also requires more time and energy being spent writing grants with the consequence being less time to engage in professional activities (e.g., reviewing manuscripts, serving on professional committees) which further hampers progress.

7. Is there anything else you’d like to tell students and postdocs within ASN?

 Invoke the word “no” as seldom as possible. Many will argue the best advice is to maintain a laser focus on one’s area of study. Not having tried this approach I can’t speak to is success. My experience is that every opportunity I’ve pursued in some way, at some time, has proven to be worthwhile.

 

Dr. Mattes’ research focuses on the areas of hunger and satiety, regulation of food intake in humans, food preferences, human cephalic phase responses and the mechanisms and functions of taste, with the objective of understanding the neural, genetic, metabolic, hormonal, cognitive, cultural and especially sensory influences on human ingestive behavior, nutrient utilization and energy balance in healthy and clinical populations.

 

As anyone in the nutrition field is aware, there are plenty of extreme dietary practices. Personally, I’ve heard about everything from the baby food diet to the Dukan diet to something about alkaline blood levels. Usually, these extreme dietary practices are met with an eye roll, knowing that these outrageous diets will last about as long as an avocado in it’s prime. But what if there was a dietary trend that promised long-term health benefits that focused not necessarily on what you eat, but when you eat?

Intermittent fasting is any period of voluntary food restriction. Protocols are varied and might include religious fasting, time restricted feeding (i.e. eating all calories within a short time window) or scheduled days of extreme caloric restriction (i.e. ≤ 25% of energy needs) followed by normal or high calorie days.

I am always skeptical of any diet or dietary pattern that claims to fix everything from obesity to cancer, but – bro-science aside – intermittent fasting is gaining a substantial amount of attention in research. A recent and thorough review in The Annual Review of Nutrition concluded that intermittent fasting might be a viable strategy to benefit overall human health, including improvements in biomarkers associated with chronic disease. Notably, however, most human research studies are limited by small sample sizes, lack of control groups, insufficient follow-up, and inclusion of normal weight or healthy individuals who are unlikely to respond to interventions.

The best diet for optimal health is one that is maintainable. A large (n=100) and long (1 year) study in metabolically healthy obese adults published last year found that drop-out was highest in the group randomized to alternate-day fasting. The long-term adherence to intermittent fasting and applicability to public health is therefore questionable.

Diet quantity and quality will always be paramount for the promotion of optimal health and healthy aging. For me, I couldn’t live without my morning matcha latte and eggs… but maybe breakfast isn’t the most important meal of the day, at least for habitual non-breakfast eaters.

These days you can hardly watch a T.V. program without being bombarded by the newest diet craze. Maybe it’s the time of year, January, when everyone is hoping to make 2018 their year, but more likely it is because dieting has become a multi-billion-dollar industry in the United States.

 

As a new-ish mother I’ve been carrying around the last 5, 10, okay 15 pounds for the last 7 months and decided in a sleep deprived haze to attempt a weight loss intervention for 2018. I was immediately overwhelmed by the number of programs, quick fixes, and suspicious non-FDA approved ‘supplements’ floating around on the market.

 

While all of these diets certainly have their individual gimmicks, they center around the core idea of calories in vs calories out. This core tenant of weight loss has been recognized as the hallmark of successful lifestyle change, that is, to lose weight one must intake less energy than they expend. While there are multiple ways to achieve this negative energy balance (i.e. diet, exercise, weight loss surgery, pharmaceuticals, etc.) I was interested in how to achieve negative balance while retaining a healthy breastmilk supply.

 

Breastmilk is composed of the 3 major macronutrients: fat, protein, and carbohydrate. Of these, mature breastmilk (that produced around day 6), contains 3.5 g of fat, 7 g of carbohydrate, and 0.9 g protein per 100ml. It also contains a whole host of other vitamins, minerals, immunoglobulins, and bioactive factors (1).  Most of the papers examining breastmilk composition in well controlled studies focus on diversity and amount of specific Fatty Acids, total protein profile, and total energy content (2). Multiple studies have also focused on the amount of DHA passed in breastmilk and linked it to maternal consumption of fatty fish (2).

 

While the outcomes of these studies showed associations of maternal diet with breastmilk composition only one well controlled study has been done to address the effects of following a diet (low carbohydrate or low fat) on the composition and supply of breastmilk. This study found that under moderate caloric restriction women on a ‘low’ (~31%) carbohydrate diets (vs low fat diets ~26% fat) had higher levels of fat in their breastmilk with higher levels of energy expenditure. Neither diet impacted breastmilk production as both were only moderately hypocaloric (3).

So where does that leave us?

 

We know women are likely to gain and retain weight during a first pregnancy putting them at higher risk for complications should a second pregnancy be desired. It appears that the most important time for weight loss interventions is the first 18 months post-partum after which weight loss tends to plateau (4). With the importance of exclusively breastfeeding up to a year we need more studies that focus on effective weight loss techniques for post-partum women who wish to maintain milk supply.

 

As for me? I think I’ll cut out the bread and leave the butter.

 

 

 

 

1) World Health Organization. “Infant and young child feeding: model chapter for textbooks for medical students and allied health professionals.” (2009).

 

2) Bravi, Francesca, et al. “Impact of maternal nutrition on breast-milk composition: a systematic review, 2.” The American journal of clinical nutrition 104.3 (2016): 646-662.

 

3) Mohammad, Mahmoud A., Agneta L. Sunehag, and Morey W. Haymond. “Effect of dietary macronutrient composition under moderate hypocaloric intake on maternal adaptation during lactation–.” The American journal of clinical nutrition 89.6 (2009): 1821-1827.

 

4) Gunderson, Erica P. “Childbearing and obesity in women: weight before, during, and after pregnancy.” Obstetrics and Gynecology Clinics 36.2 (2009): 317-332.