Does Processed Food Cause Cancer?

Written by Dr. Steve Chaney on . Posted in Processed Food and Cancer

What Are Processed Foods Doing To Your Health?

Author: Dr. Stephen Chaney

 

does processed food cause cancerDoes processed food cause cancer?

We Americans have a love, hate relationship with processed foods. We love how they taste. We love the convenience. All our friends eat them, so it is the socially acceptable thing to do. But, we also worry about them. We know they aren’t good for us.

We know they increase our risk of becoming obese. We have been warned that they may increase our risk of heart disease, diabetes, and hypertension. But, what if they also increased our risk of cancer? A new study strongly suggests that ultra-processed foods significantly increase our cancer risk.

What Are Ultra-Processed Foods?

udoes processed food cause cancer ultra processed foodsUntil recently it had been very difficult to determine the effect of processed foods on our health because there was no uniform system for classifying the processed food content of our diet. With no consistent classification system, the outcomes varied from one study to the next. That changed around 2016 with the development of the NOVA food classification system. The NOVA system divides foods into four categories:

 

  • Ultra-processed foods.
    • These are foods most Americans would consider junk foods.

 

  • Commercially Processed foods.
    • These are commercially processed foods using natural ingredients like salt, sugar, and fats. For example, frozen peas would be considered a minimally processed food (category 4). Frozen peas with added salt or frozen creamed peas would be considered a commercially process food.

 

  • Restaurant Foods.
    • These are foods processed in a kitchen (either in people’s homes or a restaurant) using salt, sugar, and/or fats to produce a culinary masterpiece (As you might suspect from the emphasis on culinary masterpiece, this is a European classification system).

 

  • Unprocessed or minimally processed foods.
    • These are foods that most Americans would consider whole foods. They are either raw or minimally processed.

 

Intuitively, you have probably already guessed that foods in category 1 are likely to be bad for us and foods in category 4 are likely to be good for us. Categories 2 and 3 start with healthy foods but often end up with foods that are higher in salt, sugar, and/or fat than most experts would consider to be healthy.

With this classification system in mind, the next step was to classify every food in large food databases into one of these four categories. In this case the 3,300 item French NutriNet-Santé food composition database was used.

 

How Was The Study Performed?

does processed food cause cancer studyThis study (T. Fiolet et al, British Medical Journal, 2018;360:k322 doi: 10.1136/bmj.k322) was performed as part of the 8-year NutriNet-Santé web-based program launched in France in 2009 with the objective of studying the associations between nutrition and health. This study enrolled 104,980 participants who were 18 or older. The average age of participants was 42.8 years. There were 82% women and 18% men enrolled in the study.

Dietary intake was assessed using an online 24-hour dietary recall survey administered every 6 months over a two-year period. The survey was administered on random days so that every day of the week was covered in the survey. On average, participants completed 5 diet surveys during the study. The validity of these dietary surveys has been established in other studies that were part of this project.

Over an average 5-year follow-up, cancer incidence was assessed via a check-up questionnaire for health events that was administered every three months.  Participants were also encouraged to self-report health events at any time. Any time a cancer diagnosis was received, a physician from the study team contacted the participant and requested their medical records, which were provided in 80% of the cases. Finally, French death records were also screened to identify any study participants who died from cancer during the study.

In short, this was a very well-done study.

 

Does Processed Food Cause Cancer?

 

does processed food cause cancer junk foodsUsing the NOVA classification system, this question is concerning ultra-processed food.

Here is what the study showed:

  • Every 10% increase in the proportion of ultra-processed foods (junk foods) in the diet was associated with a 12% increase in overall cancer and a 11% increase in breast cancer.
  • No association was seen between commercially processed foods or restaurant foods in the diet and cancer.
  • Every 10% increase in the proportion of unprocessed foods in the diet was associated with a 9% decrease in overall cancer and a 58% decrease in breast cancer.

Just in case you might be tempted to say that a 12% increase in cancer risk is insignificant, remember it is the cancer risk associated with just a 10% increase in ultra-processed foods in the diet. Recent studies have suggested that ultra-processed foods contribute from 25% to 50% of the calories consumed by most Americans.

The authors concluded “[The] rapidly increasing consumption of ultra-processed foods may drive an increased burden of cancer and other non-communicable disease.”

 

What Does This Study Mean For You?

does processed food cause cancer unprocessed foodsBecause the NOVA classification system for identifying the processed food composition of the diet is a recent introduction, this is the first study of its kind. While it is a very good study, it needs to be confirmed by further studies in different population groups.

It would be tempting to ascribe the higher cancer incidence to secondary consequences of ultra-processed food consumption. For example, consumption of ultra-processed food is associated with:

  • Obesity which, in turn, is associated with increased cancer risk.
  • Increased intake of fat, saturated and trans fats, and sugar and decreased intake of fiber and essential nutrients. The effect of these dietary changes is uncertain but could be associated with higher cancer risk.
  • Decreased intake of fruits, vegetables, and whole grains which would result in increased cancer risk.
  • Increased intake of neoformed contaminants (a fancy term for contaminants formed during processing such as acrylamide, heterocyclic amines, and polyaromatic hydrocarbons). These are all carcinogenic compounds. They are usually present in very small amounts, so their effect on cancer risk is uncertain.
  • Increased consumption of food additives of uncertain safety.

While this is an interesting area for future research, it represents a danger and shows that we will try to “have our cake and eat it too.”  Let me explain what I mean by that.

  • does processed food cause cancer restaurant foodWe love our junk foods. Food manufacturers will be only too happy to provide us with “healthier junk foods” by removing salt, sugar, and/or fat and replacing them with a chemical smorgasbord of artificial ingredients. They will reduce calories (again by adding artificial ingredients) so they can claim their junk foods won’t make us fat. They can reduce neoformed contaminants like acrylamide and claim their junk foods are now healthy. But, are they really any healthier? Not necessarily, according to this study.
  • The investigators performed a very sophisticated statistical analysis. The 12% increase in cancer they reported had already been adjusted for differences in age, sex, BMI (a measure of obesity), physical activity, smoking habits, alcohol intake, family history of cancer, and educational level. They also adjusted for fat, salt, and sugar content of the diet.
  • Some supplement companies may tell you that it’s OK to eat junk foods as long as you take the supplements they are trying to sell you. I have head dietitians say it’s OK to eat junk foods as long as you “balance” your diet with lots of fruits and vegetables. The results of this study suggest those approaches won’t be much help either.
  • Further analysis of their data by the investigators showed that the 12% increase in cancer risk was independent of overall fruit and vegetable consumption and supplement use.

The only variables left were increased intake of food additives and neoformed contaminants, and it is unlikely that those would have been sufficient to cause a 12% increase in cancer.

So, does processed food cause cancer?

Once again it appears to be the foods we eat rather than the individual components in those foods that are either good for us or bad for us. The inescapable conclusion from this study is that we are more likely to be healthy if we eat fewer processed foods and more unprocessed foods. Who would have guessed?

 

The Bottom Line:

 

A recent study looked at the effect of ultra-processed foods (otherwise known as junk foods) on cancer  risk. This was a very well-designed study, and it showed.

  • Every 10% increase in the proportion of ultra-processed foods in the diet was associated with a 12% increase in overall cancer and a 11% increase in breast cancer.
  • Every 10% increase in the proportion of unprocessed foods in the diet was associated with a 9% decrease in overall cancer and a 58% decrease in breast cancer.

Just in case you might be tempted to say that a 12% increase in cancer risk is insignificant, remember it is the cancer risk associated with just a 10% increase in ultra-processed foods in the diet. Recent studies have suggested that ultra-processed foods contribute from 25% to 50% of the calories consumed by most Americans.

This is the first study of its kind. While it is a very good study, it needs to be confirmed by further studies in different population groups.

When you look at the details of this study it appears to be the foods we eat rather than the individual components in those foods that are either good for us or bad for us. The inescapable conclusion from this study is that we are more likely to be healthy if we eat fewer processed foods and more unprocessed foods. Who would have guessed?

For more details, read the article above:

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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Comments (1)

  • Kathryn Farries

    |

    Dr Chaney,

    Thank you. Again!
    This information is very well explained. And it should be confirmation that what you don’t know can/might kill you.

    Regards,
    Kathryn

    Reply

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Latest Article

Does Protein Supplement Timing Matter?

Posted May 15, 2018 by Dr. Steve Chaney

How Do You Gain Muscle Mass & Lose Fat Mass?

Author: Dr. Stephen Chaney

 

protein supplement timingMost of what you read about protein supplements on the internet is wrong. That is because most published studies on protein supplements:

  • Are very small
  • Are not double blinded.
    • Both the subjects and the investigators knew who got the protein supplement.
  • Are done by individual companies with their product.
    • You have no idea which ingredients are in their product are responsible for the effects they report.
    • You have no idea how their product compares with other protein products.
    • There is no standardization with respect to the amount or type of protein or the addition of non-protein ingredients.

Because of these limitations there is a lot of misleading information on the benefits of protein supplements timing and maximal benefit. Let’s start by looking at why people use protein supplements. Let’s also look at what is generally accepted as true with respect to the best supplement timing.

There are 4 major reasons people consume protein supplements:

  • Enhance the muscle gain associated with resistance training: In this case, protein supplements are customarily consumed concurrently with the workout.
  • Preserve muscle and accelerate fat loss while on a weight loss diet: In this case, protein supplements are customarily consumed with meals or as meal replacements.
  • Provide a healthier protein source. In this case, protein supplements are customarily consumed with meals in place of meat protein.
  • Prevent muscle loss associated with aging or illness. There is no customary pattern associated with this use of protein supplements.

How good are the data supporting the customary timing of protein supplementation? The answer is: Not very good. The timing is based on a collection of weak studies which do not always agree with each other.

The current study  (J.L. Hudson et al, Nutrition Reviews, 76: 461-468, 2018 ) was designed to fill this void in our knowledge. It is a meta-analysis that compares all reasonably good studies that have looked at the effect of protein supplement timing on weight gain or loss, lean muscle mass gain, fat loss, and the ratio of lean muscle mass to fat mass.

How Was The Study Done?

The authors started by doing a literature search of all studies that met the following criteria:

  • The study was a randomized control trial with parallel design. This means that study contained a control group. It does not mean that the investigators or subjects were blinded with respect to which subjects used a protein supplement and which did not.
  • The subjects were engaged in resistance training.
  • The study lasted 6 weeks or longer.
  • Reliable methods were used to measure body composition (lean muscle mass and fat mass).
  • The subjects were healthy and at least 19 years old.
  • There was no restriction on the food the subjects consumed.

The authors started with 2074 published studies and ended up with 34 that met all their criteria. They then separated the studies into two groups – those in which the protein supplements were used with meals and those in which the protein supplements were used between meals.

Both groups were diverse.

  • Group 1 included subjects who consumed their protein supplement with their meal and those who consumed their protein supplement as a meal replacement.
  • Group 2 included subjects who consumed their protein supplement concurrent with exercise (usually immediately after exercise) and those who consumed their protein supplement at a fixed time of day not associated with exercise.

Does Protein Supplement Timing Matter?

 

protein supplement timing workoutsBecause the individual studies were very diverse in the way they were designed, the authors could not calculate a reliable estimate of how much lean muscle mass was increased or fat mass was decreased. Instead, they calculated the percentage of studies showing an increase in lean muscle mass or a decrease in fat mass.

When the authors compared protein supplements consumed with meals versus protein supplements consumed between meals:

  • Weight gain was observed in 56% of the studies of protein supplementation with meals compared to 72% of the studies of protein supplementation between meals. In other words, protein supplements consumed with meals were less likely to lead to weight gain than protein supplements consumed between meals.
  • An increase in lean muscle mass was observed in 94% of the studies of protein supplementation with meals compared to 90% of the studies of protein supplementation between meals. In other words, timing of protein supplementation did not matter with respect to increase in muscle mass.
  • A loss of fat mass was observed in 87% of the studies of protein supplementation with meals compared to 59% of the studies of protein supplementation between meals. In other words, protein supplements consumed with meals were more likely to lead to loss of fat mass.
  • An increase in the ratio of lean muscle mass to fat mass was observed in 100% of the studies of protein supplementation with meals compared to 87% of the studies of protein supplementation between meals. In short, protein supplements consumed with meals were slightly more likely to lead to an increase in the ratio of lean muscle mass to fat mass.

The following seem to suggest protein supplement timing matters:

The authors pointed out that their findings were consistent with previous studies showing that when protein supplements are consumed with a meal they displace some of the calories that otherwise would have been consumed. Simply put, people naturally compensate by eating less of other foods.

In contrast, the authors stated that previous studies have shown that when foods, especially liquid foods, are consumed as snacks (between meals), people are less likely to compensate by reducing the calories consumed in the next meal.

The others concluded: “Concurrently with resistance training, consuming protein supplements with meals, rather than between meals, may more effectively promote weight control and reduce fat mass without influencing improvements in lean [muscle] mass.”

What Are The Limitations Of The Study?

Meta-analyses such as this one, are only as good as the studies included in the meta-analysis. Unfortunately, most sports nutrition studies are very weak studies. Thus, this meta-analysis is a perfect example of the “Garbage In: Garbage Out (GI:GO)” phenomenon.

For example, let’s start by looking at what the term “protein supplement” meant.

  • Because the studies were done by individual companies with their product, the protein supplements in this meta-analysis:
    • Included whey, casein, soy, bovine colostrum, rice or combinations of protein sources.
    • Were isolates, concentrates, or hydrolysates.
    • Contained various additions like creatine, amino acids, and carbohydrate.
  • As I discuss in my book, Slaying the Food Myths, previous studies have shown that optimal protein and leucine levels are needed to maximize the increase in muscle mass and decrease in fat mass associated with resistance exercise. However, neither protein nor leucine levels were standardized in the protein supplements included in this meta-analysis.
  • Previous studies have shown that protein supplements that have little effect on blood sugar levels (have a low glycemic index) are more likely to curb appetite. However, glycemic index was not standardized for the protein supplements included in this meta-analysis.

protein supplement timing workout peopleIn short, the conclusions of this study might be true for some protein supplements, but not for others. We have no way of knowing.

We also need to consider the composition of the two groups.

  • Protein supplements used as meal replacements are more likely to decrease weight and fat mass than protein supplements consumed with meals. Yet, both were included in group 1.
  • Some studies suggest that protein supplements consumed concurrent with resistance exercise are more likely to increase muscle mass than protein supplements consumed another time of day. Yet, both are included in group 2. We also have no idea whether the meals with protein supplements in group 1 were consumed shortly after exercise or at an entirely different time of day.

This was the most glaring weakness of the study because it was completely avoidable. The authors could have grouped the studies into categories that made more sense.

In other words, there are multiple weaknesses that limit the predictive power of this study.

What Can We Learn From This Study?

Despite its many limitations, this study does remind us that protein supplements do have calories. This is of relatively little importance for people whose primary goal is to increase lean muscle mass.

However, most of us are using protein supplements to lose weight or to increase our lean mass to fat mass ratio. Simply put, we are either trying to lean out (shape up) or lose weight. And, we want to lose that weight primarily by getting rid of excess fat. For us, calories do matter. With that in mind:

  • If we are consuming a protein supplement immediately after exercise or between meals we probably should make a conscious effort to reduce our daily caloric intake elsewhere in our diet.
  • Alternatively, we could consume the protein supplement with a meal, but time the meal so it occurs shortly after exercise.

 

The Bottom Line:

 

A recent study looked at the optimal timing of protein supplements consumed by subjects who were engaged in resistance exercise. Specifically, the study compared protein supplements consumed with meals versus protein supplements consumed between meals on weight, lean muscle mass, fat mass, and the ratio of lean muscle mass to fat mass. The study reported:

  • Protein supplements consumed with meals were less likely to lead to weight gain than protein supplements consumed between meals.
  • Timing of protein supplementation did not matter with respect to increase in muscle mass.
  • Protein supplements consumed with meals were more likely to lead to loss of fat mass.
  • Protein supplements consumed with meals were slightly more likely to lead to an increase in the ratio of lean mass to fat mass.

The authors pointed out that their findings were consistent with previous studies showing that when a protein supplement was consumed with a meal it displaces some of the calories that would have been otherwise consumed. Simply put, people naturally compensate by eating less of other foods.

In contrast, the authors said that previous studies have shown that when foods, especially liquid foods, are consumed as snacks (between meals), people are less likely to compensate by reducing the calories consumed in the next meal.

As discussed in the article above, the study has major weaknesses. However, despite its many weaknesses, this study does remind us that protein supplements do have calories. This is of relatively little importance for people whose primary goal is to increase lean muscle mass.

However, for those of us who are using protein supplements to lose weight or to increase our lean mass to fat mass ratio, calories do matter.  With that in mind:

  • If we are consuming a protein supplement immediately after exercise or between meals we probably should make a conscious effort to reduce our daily caloric intake elsewhere in our diet.
  • Alternatively, we could consume the protein supplement with a meal, but time the meal so it occurs shortly after exercise.

For more details, read the article above:

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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