Tag Archive for: cancer

The Bottom Line on Sugary Drinks and Cancer

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The question is simple: do we avoid all sugary drinks, including fruit juices? The best I can come up with is to withhold judgment and don’t get excited about it for now. Let’s take a look at what the concerns of the researchers were and then my concerns.

Researchers’ Concerns

The first is that the NutriNet-Santé study was not a randomized sample. That means that only those people who were interested in participating for whatever reason did so. The sample was predominantly women at 78.7% of the cohort with a mean age of 42 years. The researchers accounted for age and gender in the statistical analyses, but that doesn’t account for the lack of randomization.

Researchers also stated that the rate of cancer was much lower: 620 of the 100,000 people in the study compared with 972 per 100,000 people in all of France. They adjusted the numbers to reflect the age and gender distribution in France, but I used the numbers actually given in the study. They also said the diagnosis of cancer was self-reported. I can’t believe anyone would say they have cancer if they don’t, but it would have been better if it were verified.

Related to that, some cancers were limited, thus affecting the statistics. If you don’t have enough of any type of cancer, it’s difficult and scientifically shaky to calculate a relationship.

Younger subjects consumed higher amounts of sugary drinks than older subjects. There were other factors as well, but these also were taken care of statistically. Further, they acknowledge what I alluded to: when people self-report, they can over- and under-estimate their intake. They also chose only the subjects that had at least two diet records completed in the first two years; the potential was 10 if all records were completed by all subjects. That seems low to me—there’s too much missing data.

Finally, this was an observational study and thus cause and effect can’t be attributed to the results. But it does raise questions.

My Questions

I think they could have gone a long way to answering the question about sugar intake if they had compared the fruit intake with the juice intake: take the fruit intake, calculate the sugar content, then match it with juice intake with the same sugar content. What was the rate of cancer in each group? Doing the direct comparison could go a long way to suggest whether it’s the sugar alone or if the effects were ameliorated with the fiber and phytonutrients of whole fruit with the same amount of sugar. That’s an obvious question; this is an ongoing study so maybe they’ll do that in the future.

I also think that running a comparison of total carbohydrate intake could also give us insight. If someone had a high carbohydrate intake, especially if it were high in refined carbohydrates, that might be meaningful as well.

The Bottom Line

The question I was left with was this: how could less than a half-cup per day of any type of added sugary drink that contained fewer than 50 sugar calories cause an increase in cancer? It just doesn’t make any kind of sense when you consider the total mean average calorie intake of the subjects was 1,850 calories. If the total sugar intake from solid foods of the individuals was high, or it was highly refined carbohydrates, that could make a difference. That analysis wasn’t done.

At this point, I wouldn’t stop drinking a glass of fruit juice or adding some juice to a smoothie. Don’t go out of your way to drink more fruit juice, but don’t avoid it either; certainly you should choose fruit juice from whole fruit over soda with sugar. If you have an artificial sweetener you like, use that instead of sugar. As for other drinks that contain sugar, they’re highly refined carbohydrates so you should be keeping those under control anyway. While this was an interesting and controversial report, nutrition is still about balance. Keep that in mind as you choose what you eat and drink every day.

What are you prepared to do today?

        Dr. Chet

Reference: BMJ 2019; 366 doi: https://doi.org/10.1136/bmj.l2408.

Finding the Cancer Risk in Sugary Drinks

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In Tuesday’s Memo, I reviewed the methodology of the NutriNet-Santé study in France. As I suggested, it was solid. The sugary drink choices included fruit juices, sodas, sugar-sweetened hot and milk beverages, sports drinks, and energy drinks. In terms of the data collection, I can’t think of anything they could have done better.

Turning to the statistical analysis, it was complicated to say the least. The use of high-speed computers allows for many statistical analyses to be done in short order, even with over 100,000 subjects. My only concern is that, as they did the trend for hazard ratios, they adjusted for many variables including age, gender, energy intake, and family history. How many variables? About 24 in all by my count. That’s not necessarily wrong, but there are some that would seem obvious such as total carbohydrate intake from all foods, and percentage of calories from carbohydrates other than vegetables and fruit.

Another way of analyzing the data was something I’ve done before, and that’s compare the rate of cancer to the national cancer statistics in France. In this case, the rate of cancer in France is 0.95% while it was 0.87% in the unadjusted data from the study. That’s very close and a bit lower than the national average.

Must we avoid even a half-cup of fruit juice per day? Is the sugar in your coffee or sweet tea causing a significant increase in your risk of getting cancer? I’ll let you know on Saturday.

What are you prepared to do today?

        Dr. Chet

Reference: BMJ 2019; 366 doi: https://doi.org/10.1136/bmj.l2408.

Is There a Link Between Sugar and Cancer?

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Sugar has been in the news with the publishing of the latest results from the NutriNet-Santé study from France. The headlines of press releases suggest that drinking as little as four ounces of a sugary drink, including fruit juice, per day was related to an increased risk of getting cancer. Sugary drinks of all types except fruit juice were associated with an increased risk of getting breast cancer. These were all hazard ratio trend analyses; as the consumption increased, so did the risk of cancer.

If you read the Memos regularly, you know my approach is to always check how the data were collected. In this study, they used three 24-hour dietary records that included two weekdays and one weekend day. The diet records were done every six months throughout the duration of the follow-up, about five years. They subjects entered their data online; with over 100,000 subjects, that’s the only way this study could be done.

Of all the types of diet assessments, this is as close to the gold standard as I’ve seen. They had 97 different sugary drinks and 12 artificially sweetened drinks that were possible choices with very detailed descriptions and photos of drinks to help assess portion size. The only step they didn’t take was to have the records checked by a dietician before the subjects entered their data online. The methods in this study were solid compared to just about every other study I’ve talked about.

Should we avoid all sugary drinks at this point? More on Thursday. Tomorrow is the July Insider Conference call; this is your chance to learn more about nutrition and get your questions answers. You can still be included, so check out memberships right now.

What are you prepared to do today?

        Dr. Chet

Reference: BMJ 2019; 366 doi: https://doi.org/10.1136/bmj.l2408.

Food Is Better Than Supplements, But …

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Getting your nutrients from food by eating a healthy diet is the most desirable way of getting vitamins, minerals, and phytonutrients. Period. If we could all do it, no question that’s the best way. But you and I don’t live in some fantasy world. We’re busy. We don’t always have enough time to shop and cook healthy meals. Dietary supplements have helped fill the nutrition gap.

What should we think about this latest research? Should we stop taking supplements, especially calcium? Before I give you my opinion, I want to tell you that I emailed the corresponding author of the paper, a brilliant woman and a talented researcher. I had two questions about the study. She answered me the same evening—Saturday night before Easter. That I got such quick reply was remarkable; I’m still waiting for answers from other researchers I contacted months ago.

The first question I asked was a basic one: what was the mortality rate of the subjects in the study compared with the national cancer mortality rate? The national mortality rate is 156 deaths per 100,000 people per year. That works out to 1.6 people per 1,000. The rate in the study was about 3 people per 1,000. She replied that the study results are not directly comparable for complicated reasons.

But here’s something that can be directly compared. A 62% increase in cancer mortality would be transferable to national statistics because that’s the idea: to generalize to the entire population. A 62% increase means that 2.5 people per 1,000 would die from cancer in a given year instead of 1.6. When applied to the entire population that could be a lot of people, but it applies only to those who took over 1,000 mg of calcium per day.

The other question I asked was whether they had data on how long the people were taking the supplements; NHANES asked about the 30 days prior and recorded the prior 24 hours. How long were they taking the supplements? Weeks? Months? Years? Decades? That might have made some difference. The data were collected in the questionnaires used for two of the cycles that I examined, but that data was not used in the analysis.


The Bottom Line

I think we should eat the best diet we can. I also think we should use quality dietary supplements to complement our diet. This study was an exercise in statistics more than nutrition. It can tell us the statistical outcomes of the people in the study, but it can’t really be used to tell us anything about what we should do as individuals.

Not every person who took a higher amount of calcium died from cancer. On top of that, if supplementation did have a significant negative impact on our health, it stands to reason there would have been more negative results than just for calcium. Because the research questions were fitted to the available data, there’s just too much we don’t know about factors that can influence the results.

Another good question the study didn’t ask is why people were taking calcium. For instance, a woman with osteoporosis may take calcium for better bone health. Did those women have fewer broken bones with supplementation? If so, that might be worth any higher risk that exists. As with any nutritional intervention, it’s important to weigh the pros and cons. If you’re concerned, talk to your healthcare professional about what you should do; they know you and your health status and can help you make the right choices.

Supplement confusion is a good reason to get a copy of my new CD Supplementing Your Diet. Check out why at drchet.com.

What are you prepared to do today?

        Dr. Chet

Reference: Ann Intern Med. doi:10.7326/M18-2478.

Food vs. Supplements: A Closer Look

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There’s no question National Health and Nutrition Examination Survey (NHANES) has done the best job of collecting data on nutritional intake in large-scale studies. I’ve applauded it in the past, and I’m not going to change now just because there’s an NHANES-based paper that critiques the use of supplements. NHANES data were used by one of the co-authors of the current research paper we’re examining; in that study, they demonstrated regular use of a multivitamin-multimineral can compensate for deficiencies in our diet.

What could explain the same data showing potential benefits and hazards of supplements? Two reasons in my opinion. First, the research questions were not part of the original study; that’s supported by the fact that the lead author would have been six or seven years old when data collection began.

Imagine you apply for a loan. You’d give the bank all kinds of financial data: your total earnings, where you work, what you owe, and so on. Then imagine that researchers take all that very accurate data and estimate your hourly wage. They could be right on the money or way off, because they don’t know how many hours you worked; that wasn’t one of the questions. It’s the same with the data in this study; the researchers can make a great guess from the data they have, but the question they’re trying to answer wasn’t one of the original questions asked so their guess may be very far from correct. That happens often in these retrospective studies.

Second, the bulk of the researchers were experts in statistics and epidemiology. The statistical analysis accounted for 11 factors to numerically make the data comparable. We can’t really know what that does to modify the data instead of collecting data on actual variables.

Still worried? I’ll finish this up on Saturday.

What are you prepared to do today?

        Dr. Chet

Reference: Ann Intern Med. doi:10.7326/M18-2478.

Food vs. Supplements

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Last week, the health headlines blared that nutrients from foods were better than nutrients from supplements—specifically that excess calcium from supplements was associated with an increased risk of dying from cancer. That will get your attention if you take supplemental calcium, especially if you’re taking calcium because your physician told you to take it because you have osteopenia or osteoporosis. Let’s take a closer look at this study published in the Annals of Internal Medicine.

Researchers examined data collected for the National Health and Nutrition Examination Survey (NHANES) on food intake and supplement use. NHANES data are now collected every two years, so they selected six consecutive cycles and tracked the all-cause mortality from subjects in those data. They found that in over 30,000 adults over 20 years of age tracked for six years, there were 3,613 deaths with 805 from cancer.

The researchers then examined the food intake and supplement use of the subjects from the prior 30 days of data collection with mortality data. That’s where they discovered that in the subjects who died from cancer, there was a 62% greater risk if they took more than 1,000 mg of supplemental calcium per day. The overall conclusion was that nutrients from foods are better than nutrients from supplements; in addition, some supplements may be hazardous.

Should you start chucking out your calcium supplements? We’ll take a closer look at this study the rest of this week.

What are you prepared to do today?

        Dr. Chet

Reference: Ann Intern Med. doi:10.7326/M18-2478.

Update: Tattoos and Cancer

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This week it’s time to update prior memos given. The first is a case study on tattoos. It seems people, especially young people, are wearing a lot more ink then they used to. I’ve written about the relationship between tattoos and cancer, but didn’t find enough data to make a recommendation. This memo is about a recent case study on tattoos and lymphoma. Or so the physician thought.

A woman noticed a couple of lumps under her armpits. She waited a couple of weeks but when they didn’t go away, she went to the doctor. The doctor examined her. The lumps were swollen lymph nodes. They did a scan of her upper body and found more lymph nodes, similarly swollen, a condition usually consistent with lymphoma. When they excised the lymph nodes, they were surprised to find that they were full of ink. Black tattoo ink. She had gotten a large tattoo on her back some 15 years prior and another one recently. No cancer, just an extreme reaction to the ink.

Skin is live tissue and it’s part of the immune system. As the physician told the media, this was an extreme immune response to an invasion by a foreign substance. The white blood cells did what they do and sequestered the ink in the lymph nodes. Why? The physicians couldn’t explain. The question is will it happen more frequently with more tattoos in the future? Only time will tell. But if you have a tattoo, this is another reason to get any lumps checked immediately.

What are you prepared to do today?

Dr. Chet

 

Reference: Ann Intern Med. 2017. DOI: 10.7326/L17-0424.

 

B6, B12, and Lung Cancer

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The overwhelming message from the study I’ve been reviewing this week: don’t smoke cigarettes. Period. That’s the true cause of most cases of lung cancer. There was no increase in lung cancer in subjects taking high doses of B6 or B12 who never smoked or in those who quit more than 10 years before the study began. While the increased risk applied only to men, women shouldn’t smoke either: 44% of those who got lung cancer were women.

For those men who still insist on smoking or quit less than ten years ago, is there anything to be concerned about if you megadose on B6 or B12? It’s hard to know for sure.

I spoke with the primary author via email. Dr. Ted Brasky and I have battled over omega-3s in the past but minor disagreements in methodologies aside, he is a top-notch researcher. He doesn’t think the B vitamins cause cancer. What he thinks may be happening is that the carcinogens in cigarette smoke cause damage to lung cell DNA, and the excess B vitamins may be enhancing the initiation of cancer. I agree with him.

The question is why might this be happening? The lack of B vitamins seems to reduce the DNA repair process, so increasing to normal levels seems to help. But overdoing it may not be beneficial. Some smokers are taking high-stress B supplements with hundreds or thousands of micrograms of B12. Those are the smokers who could be at risk.

There are two explanations that make sense to me. First, there may be a mutation in the gene that manufactures the enzyme methylenetetrahydrofolate reductase, the enzyme that helps convert homocysteine to methionine. That enzyme requires B12, but perhaps it malfunctions and the B12 becomes toxic to the cells damaged by smoking.

The second explanation comes from the article itself. When trying to explain the factors that could impact this relationship between smoking and vitamin intake, researchers suggest there may be a difference in the absorption, utilization, or distribution of the vitamins. In other words, some people may absorb more vitamin B6 or B12 than others, resulting in a higher circulating amount and thus more available for cells to use. In normal conditions that may be fine but with smoking-induced damage, it may not. The fact is we just don’t know at this time.

 

The Bottom Line

Back to addressing those headlines. If you don’t smoke, there is no problem based on this study. If you do smoke, taking a multivitamin, a B-complex with reasonable amounts of B vitamins, or using energy drinks should present no problem: the study showed no increases with the amounts found in those types of products. If you do smoke, until there is research to clarify the actual cause, limit your intake of high-stress Bs or megadoses of vitamins B6 and B12.

Or maybe the best idea is to just quit smoking. I know it’s hard; I smoked back when I was young and thought myself immortal. You have my sympathy, but my advice is to quit any way you can.

What are you prepared to do today?

Dr. Chet

 

Reference: J Clin Oncol. DOI: https://doi.org/10.1200/JCO.2017. 72.7735

Behind the Misleading B Vitamin Headlines

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Headlines are designed to be provocative. With so many sources of news to choose from, something must get you to click on that link. The problem is when the articles and posts are misleading and, in some cases, just wrong. There were primarily two things wrong about the two online articles I cited in Tuesday’s Memo. I could have picked just about any articles about the study but these were the highest profile.

First, the headlines and the body of the text in both articles implied that the increased risk applies to everyone who uses high doses of vitamins B6 and B12. That’s false. There were so few cases of lung cancer in non-smokers, they saw no reason to analyze that data. Either that’s outright deception or the reporters didn’t read the study.

Second, the word “cause” was used in some headlines, and that’s just false. This was an observational study; the original data on supplement use was collected at the beginning, and then the researchers observed the health of the subjects via a centralized medical database. That type of study shows there’s a link of some kind but cannot show cause and effect.

What did the study actually say and what did the study author say about the results? I’ll let you know on Saturday.

One more thing: we try to make our Memo headlines grab your attention by using key words or asking an intriguing question. That’s part of the business of online information. But if we ever have a headline that’s truly misleading, I expect you to call me on it. Being reliable, trustworthy, and factual are our goals.

What are you prepared to do today?

Dr. Chet

 

Reference: J Clin Oncol. DOI: https://doi.org/10.1200/JCO.2017. 72.7735

 

Do Vitamins B6 and B12 Cause Cancer in Men?

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The headline in The Atlantic said: “Vitamin B6 and B12 Supplements Appear to Cause Cancer in Men.” The Huffington Post said: “Men: Taking Vitamins B6 and B12 Could Increase Your Risk of Lung Cancer.” There were few news sources that didn’t pick up this provocative headline. As you might expect, I started to get questions about the study almost immediately from people who take B vitamins and who drink energy drinks. Exactly what is going on? That’s what we’ll examine in this week’s Memos. Today we’ll take a look at the study.

The Vitamin and Lifestyle study (VITAL) collected information from over 77,000 men and women in western Washington State. The subjects were 50 to 76 when data collection began in 2000–2002. Participants completed a detailed questionnaire on supplement use, a food frequency questionnaire for diet, and a lifestyle questionnaire focusing on risk factors for cancer. The focus was to recruit supplement users.

In an analysis of the data on smoking patterns and the use of folic acid and vitamins B6 and B12, researchers found that men who smoked while taking high amounts of vitamin B6 and B12 had a significantly increased risk of lung cancer. The same results were not found in women.

Those are the results. We’ll take a closer look at the accuracy of the headlines on Thursday.

What are you prepared to do today?

Dr. Chet

 

Reference: J Clin Oncol. DOI: https://doi.org/10.1200/JCO.2017. 72.7735