This study assessed the patterns of dietary supplement usage among cancer survivors in the United States in a population-based setting. National Health and Nutrition Examination Survey (NHANES) datasets (1999-2016) were accessed, and adult respondents (≥ 20 years old) with a known status of cancer diagnosis and a known status of dietary supplements intake were included. Multivariable logistic regression analysis was then used to assess factors associated with dietary supplements intake. Moreover, and to evaluate the impact of dietary supplements on overall survival among respondents with cancer, multivariable Cox regression analysis was conducted.

A total of 49,387 respondents were included in the current analysis, including a total of 4,575 respondents with cancer. Among respondents with cancer, 3,024 (66.1%) respondents reported the use of dietary supplements; while 1,551 (33.9%) did not report the use of dietary supplements. Using multivariable logistic regression analysis, factors associated with the use of dietary supplements included:

  • older age (OR: 1.028; 95% CI: 1.027-1.030);
  • white race (OR for black race vs. white race: 0.67; 95% CI: 0.63-0.72);
  • female gender (OR for males vs. females: 0.56; 95% CI: 0.53-0.59),
  • higher income (OR: 1.13; 95% CI: 1.11-1.14),
  • higher educational level (0.59; 95% CI: 0.56-0.63),
  • better self-reported health (OR: 1.36; 95% CI: 1.17-1.58),
  • health insurance (OR: 1.35; 95% CI: 1.27-1.44),
  • history of cancer (OR: 1.20; 95% CI: 1.10-1.31).

Using multivariable Cox regression analysis and within the subgroup of respondents with a history of cancer, the use of dietary supplements was not found to be associated with a difference in overall survival (HR: 1.13; 95% CI: 0.98-1.30).

The authors concluded that dietary supplement use has increased in the past two decades among individuals with cancer in the United States, and this increase seems to be driven mainly by an increase in the use of vitamins. The use of dietary supplements was not associated with any improvement in overall survival for respondents with cancer in the current study cohort.

Many cancer patients, when they first get diagnosed, are tested for vitamin D levels and found to be low or borderline. Consequently, they get a prescription for supplements. Other than this, there is rarely an indication to take any vitamins or other dietary supplements. Yet, cancer patients take them because they think these ‘natural’ preparations can do no harm (and because the industry can be persuasive [there is big money at stake] and the odd breed of ‘integrated’ oncologists might even recommend them). Sadly, this assumption is not correct. The biggest danger, in my view, is the possibility of supplements to interact with one of the many drugs that cancer patients need to take. So, in a way, it is reassuring that, on average, there is no detrimental effect on overall survival.

The paper will probably also reignite the perennial discussion about the effects of vitamin C on the natural history of cancer. My understanding is that there is none (and this verdict seems to be supported by the findings reported here). But I am, of course, aware that this is a ‘hot potato’ and that some readers will think differently. To them I say: please show me the evidence.

15 Responses to Dietary Supplements for Cancer Patients: NO EFFECT ON OVERALL SURVIVAL

  • Same kind of poor science as the mindfulness study. They are taking the sickest population, cancer patients, and making no selection for the quality of the nutritional program they are on. LOOK! Big surprise! No statistically significant benefit to taking supplements in this population. Therefore the implication is supplements must be useless. Amazing how every so often they publish these studies using the worst protocol design and the sickest population “proving” supplements are useless. I wonder why.

    Why, I’ll bet taking those Centrum tablets allowed Mrs X with stage 4 liver cancer to live 16 hrs longer.

  • “Most patients reported using dietary supplements because it was something they could do to help themselves (56.2%)” and/or give them more energy (43.6%). Only 20.2% used supplements to try and prevent cancer.

    “Patients’ physicians were the most common source of information (47.3%)”

    J Altern Complement Med. 2009 Jun; 15(6): 673–680.

  • Homeopathic medicines to the rescue…at least for those of you who believe in EVIDENCE BASED MEDICINE (which sadly is not too many people here who instead carry big axes to grind).

    Homeopathic Treatment as an ‘Add on’ Therapy May Improve Quality of Life and Prolong Survival in Patients with Non-Small Cell Lung Cancer: A Prospective, Randomized, Placebo-Controlled, Double-Blind, Three-Arm, Multicenter Study

    • much obliged Dana; I will discuss it tomorrow on this blog

      • “I will discuss it tomorrow on this blog”

        Ernst, every time you say that, I get ready to watch a movie where you set up your own adventures. You are so predictable in your writings that before you read the paper you already have a conclusion. Your choices are reduced to saying that if the study is high quality and positive, you close with your opinion saying that it can not be positive because it uses a design A + B, blah, blah, or disqualify the authors saying that they are “homeopaths”, “acupuncturists”, or because any of them affiliated with a research center of Complementary Medicine. But this is not enough, you will allude to being “implausible”, ignoring all the accumulated mass of evidence, or you will appeal to your social circle of pseudoexperts to find from some misspelling to torturing the data, followed by Lenny’s unsubstantiated comments or Mojo’s insults.

        • Lols

          Strange isn’t it how you still haven’t produced that great bit of in vivo clinical evidence which will silence us. Dana waved about a bit of unreproduced tripe from 20 years ago. You continue to clatter on about homeopaths and their ongoing laboratory efforts at looking down microscopes to see how many angels are dancing on the pinhead today.

          Meanwhile science and medicine, knowing homeopathy to be the twaddle it has been shown to be, continues to ignore it.

          As ever, it would be easy to shut us up. As ever, in a blinded trial, identify some homeopathic remedies. You can choose which remedies you’ll have to tell apart. Should be simple. Roger should be able to do so by doing some provings. Somehow, though, homeopaths continue to dodge and evade the challenge.

          Because they know they’ll fail and the house of cards will come tumbling down.

          As you were, Lols. Keep flanneling.

    • A versus A+B



      You never learn do you, Dana?

      And you wouldn’t recognise proper evidence if it bit you on the arse.

      • Lenny…you’re not asleep…you’re in a deep coma. My sympathies.

        BTW, who cares whether you think about A vs A+B. This is ONE of the ways that good science evaluates.

        • No, Dana. It’s one of the ways that shit science tries to pull the wool over peoples’ eyes. It’s why crap like that study gets ignored by everyone except halfwits like you.

        • “BTW, who cares whether you think about A vs A+B.”

          Science cares, Dana.

          @Lenny: Perhaps if you dilute your science to 100C, then it might work on Dana?

          On second thoughts, better go with 200C. Dana’s grasp of science is 100C as it is.

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