• 80% of North-Americans and 75% of Europeans are deficient in vitamin D. Vitamin D status is lowest at the end of Winter (February/March in the Northern hemisphere). Yet, vitamin D is a natural compound that is essential to numerous biological functions.

  • The scientists recommend that physicians identify and correct vitamin D deficits, in priority among people with serious chronic illnesses such as cancer, heart disease and osteoporosis.

  • The scientists call on the health authorities of each country to establish a public health recommendation for adequate supplementation of vitamin D based on the most recent studies with the aim of correcting the widespread deficit of the population.

    • Vitamin D is Required for Optimal Health

    Substantial scientific evidence now exists supporting the role of vitamin D in prevention of cancer. Multiple research findings have reasonably established that an adequate serum vitamin D status is independently associated with substantially lower incidence rates of several types of cancer, including breast, colon, ovary, non-Hodgkin’s lymphoma, and several other types. Vitamin D

    Scientific studies show that the vitamin D status (i.e., serum 25-hydroxyvitamin D level) of most individuals in North America and Europe needs to be greatly improved for substantial reduction in incidence of and mortality from cancer. In addition to cancer, epidemiological studies have shown that higher vitamin D status is also associated with lower risk of several other chronic diseases, including heart disease, stroke, osteoporosis, multiple sclerosis, and type 1 diabetes in children. Several studies have found that higher serum vitamin D status is also associated with lower incidence and severity of influenza, pneumonia, and several other infectious diseases.

    Most of the Population is Deficient in Vitamin D

    Recent studies show that a preferred range of serum 25-hydroxyvitamin D should be 75–150 nmol/L (30–60 ng/mL). In the United States, an estimated almost 80% of persons of all age groups have an insufficient status of vitamin D (serum 25-hydroxyvitamin D level less than 75 nmol/L or 30 ng/mL). In France, the SU.VI.MAX study has demonstrated that more than 70% of adult men and women have an insufficient status. As for menopausal women, a large European study estimated that 79.6% have an insufficient status across different European countries, and that number was 90.4% in France.

    Higher vitamin D status can be achieved by increased oral intake of vitamin D or appropriate sun exposure (without a significantly increased risk of skin cancers). The appropriate intake of vitamin D for cancer risk reduction depends on the individual’s age, skin type, lifestyle, and latitude of residence. Recent scientific evidence indicates that intakes of 1000–2000 IU per day could prevent a substantial proportion of cancers and would also be effective in reducing risks of falls, fractures, heart diseases and strokes, multiple sclerosis, and type I childhood diabetes.

    Greater oral intake of vitamin D may be required in the aged and in individuals who spend little time outdoors, people who avoid sunlight exposure, or in dark-skinned people living in temperate climates because of reduced cutaneous synthesis from sun exposure. Choice of a larger dose may be based on each individual’s serum status of wintertime 25-hydroxyvitamin D as determined by a health care practitioner.

    For those in whom serum vitamin D status is tested, a target serum level of 25-hydroxyvitamin D should be chosen in consultation with a health care provider, based on the characteristics of the individual. An approximate guideline for health care providers who choose to measure serum vitamin D status in their patients would be to aim for 75–150 nmol/L (30–60 ng/mL), barring specific contraindications. Contraindications are rare and are known to physicians. No intervention is free of all risk, including this one. Patients should be aware of this fact and advised in detail of risks that may be specific to the individual.

    Already, the Canadian Cancer Society is recommending a specific level of vitamin D supplementation: 1000 IU per day during the fall and winter for all Canadians and 1000 IU per day all year round for adults at higher risk of having lower vitamin D levels (i.e., older people, subjects who do not go outside often, or people with dark skin).

    Our Conclusions:
    A substantially higher level of support for research on the role of vitamin D for the prevention of cancer and other chronic diseases is needed. However, from current evidence we recommend the following:

    • For most people suffering from cancer, heart disease, osteoporosis, chronic kidney disease, or other conditions associated with a vitamin D deficiency, people older than 60 years, and people of dark skin to seek appropriate serum testing of 25-OH vitamin D from their health care practitioners. On the basis of this testing, we further recommend adequate supplementation or appropriate sun exposure to maintain a year-round level of 25-OH vitamin D between 75 and 150 nmol/L (30–60 ng/mL).

    • For the population at large, an urgent reflection of the appropriate health authorities of each country on the importance of recommending supplementation of 1000–2000 IU of vitamin D per day, especially during the fall and winter months.
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    Frequently Asked Questions

    • Is a deficit of vitamin D a cause of illness or a symptom only?

      Population studies have consistently demonstrated that a low serum vitamin D status is associated with an increased risk of several serious diseases. But is it because low vitamin D status contributes to illness, or could it be that several chronic diseases reduce vitamin D status in the body? The latter is unlikely to be the case because several studies finding increased risk of disease among subjects with low vitamin D status measured serum vitamin D level long before the appearance of cancer or other diseases. Also, several intervention studies have found that increasing vitamin D status through deliberate ultraviolet-B exposure or with vitamin D supplements improves health status or reduces disease risk. This effect has been reported for falls and nonvertebral fractures in the elderly, arterial hypertension, and, in one study each, for cancer (several types) in postmenopausal women or influenza infections in dark-skinned women.

    • Does exposing your skin to the sun without sunscreen increase the risk of skin cancer?

      Unprotected sun exposure for prolonged periods is associated with an increased risk of skin cancer—mostly nonmelanoma skin cancer, the type that is easily treated when detected early. In adulthood, sun exposure as needed for the synthesis of vitamin D (of the order of 20 minutes a day) is not associated with any significant increased risk of skin cancer and specifically not of melanoma. Children in particular should be carefully protected from sunburns.

    • What about studies showing no benefit of supplementing with vitamin D for cancer risk reduction?

      The large Women’s Health Study did not find a reduction in cancer risk with vitamin D supplementation. However, the dose of vitamin D used in this study was 400 IU, almost one-third of the dose that led to a significant reduction of cancer risk in a later study (1100 IU).

    • What about the risk of vitamin D toxicity?

      To this day, medical textbooks mention the risk of vitamin D toxicity. Yet, the scientific literature suggests that toxicity occurs only with very large intakes of vitamin D over prolonged periods (more than 10,000 IUs daily for longer than 6 months). Except in people with disorders known as granulomatosis (such as sarcoidosis or tuberculosis), little risk (if any) is associated with vitamin D supplementation of 1000–2000 IU per day.


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    The 40 Scientists and Physicians

    - David Servan-Schreiber, MD, PhD – Clinical Professor of Psychiatry, University of Pittsburgh, USA

    - Annie J. Sasco, MD, DrPH, Director Group of Epidemiology for Cancer Prevention, Inserm and Université Victor Segalen, Bordeaux, France

    - Jean-Claude Souberbielle, PhD - Hopital Necker-Enfants malades et Université Paris Descartes, France

    - Barbara Boucher, MD, Queen Mary University of London, Blizard Institute of Cell and Molecular Science, London, U.K.

    - Carlos A. Camargo Jr, MD, DrPH, Associate professor of Medecine, Massachusetts General Hospital, Harvard Medical School, Boston, USA

    - Pr. Vincent Castronovo, M.D., Ph.D, Breast Cancer Oncologist, Chairman, Department of Biology, Faculty of Medicine, Director, Metastasis Research Laboratory, Head of GIGA-Cancer, University of Liege, Belgium

    - Etienne Cavalier, PhD, Service de Chimie Médicale, CHU Sart Tilman, Liège, Belgique

    - Laurent Chevallier, MD, Praticien Attaché au CHU de Montpellier. Enseignement de nutrition à l'Université. Président de la Commission Alimentation du Réseau Environnement Santé

    - Catherine Cormier, MD, Service de rhumatologie, Hôpital Cochin , Paris, France

    - Heidi Cross, MD, Professor, retired from the Department of Pathophysiology, University of Medicine, Vienna, Austria

    - Pr. Harald Dobnig, MD, Klinische Abteilung für Endokrinologie und Nuklearmedizin, Univ.-Klinik für Innere Medizin,Medizinische Universität, Graz, Austria

    - Pr. Patrice Fardellone, chef de service de Rhumatologie, CHU d'Amiens, France

    - Pr. François Feron, Neurobiologie des Interactions Cellulaires et Neurophysiopathologie, CNRS UMR 6184, Faculté de Médecine Nord, Université Aix Marseille

    - Pr Gérard Friedlander, Chef de service des Explorations Fonctionnelles hôpital Européen Georges Pompidou et hôpital Necker-Enfants malades, Paris.et centre de recherche "croissance et développement", directeur de l'unité Inserm 845 (homéostasie du phosphate), France

    - Stephen Genuis, MD, Clinical Associate Professor in the Faculty of Medicine at the University of Alberta, Canada

    - Edward Giovannucci, MD, PhD, Professor of Nutrition and Epidemiology, Harvard Medical School, Boston, USA

    - Adrian F. Gombart, PhD, Associate Professor, Linus Pauling Institute, Department of Biochemistry and Biophysics, Oregon State University, USA

    - Edward D. Gorham, MPH, PhD, Associate Professor, Moores Cancer Center and Dept of Family and Preventive Medicine, University of California, San Diego, USA

    - William B. Grant, PhD - Sunlight, Nutrition and Health Research Center (SUNARC)

    - Pierre S. Haddad, Ph.D. Professeur titulaire, Département de pharmacologie, Faculté de médecine, Université de Montréal, Canada

    - Robert P. Heaney, MD, John A. Creighton University Professor & Professor of Medicine, Creighton University Medical Center, Omaha, USA

    - Martin Hewison, PhD, Professor of Orthopedic Surgery, University of California at Los Angeles, USA

    - Michael F. Holick, MD, PhD - Professor of medicine, physiology and biophysics, Boston University School of Medicine, USA

    - Bruce W. Hollis, MD, Professor of Pediatrics, and Biochemsistry and Molecular Biology, Director of Pediatric Nutritional Sciences, Medical University of South Carolina

    - Christian Jamin MD, spécialiste en médecine interne endorcinologie de la reproduction et cancer du sein, president de l’Association Française pour l'Après Cancer du Sein (AFACS), Paris, France

    - Guillaume Jean, MD, Centre de Rein Artificiel, Service de Néphrologie Hémodialyse, Tassin, France. - Joan M. Lappe, PhD, Professor of Medicine, Creighton University, Omaha, USA

    - Pr Jean-Michel Lecerf, Service de Nutrition Institut Pasteur et Centre Hospitalier Universitaire de Lille, France - Marie France Le Goaziou, MD, Coordonnatrice du DES de médecine générale, Université Claude Bernard LYON1, France

    - Pr Ziad Massy, Division de Pharmacologie et Nephrologie, Université de Picardie – Jules Vernes, INSERM ERI-12 et Centre Hospitalier Universitaire d’Amiens, France

    - Jean-Loup Mouysset, MD, Medical Oncologist, Polyclinique Rambot-Provençale, Aix-en-Provence, Président de l’association Ressource

    - Pr. Charles Pierrot-Deseilligny Service de Neurologie, hôpital de la Salpêtrière, Assistance Publique Hôpitaux de Paris, France

    - Stefan Pilz, MD Department of Internal Medicine, Division of Endocrinology and Nuclear Medicine, Medical University of Graz, Austria

    - Gregory A. Plotnikoff, MD, Medical Director, Center for Integrative Medicine, Abbott Northwestern Hospital, Minneapolis, MN

    - Pr. Dominique Prié, service d'Explorations Fonctionnelles Hôpital Necker-Enfants malades Faculté de médecine Necker, Université Paris-Descartes, France

    - Simone Saez, MD, Dr Human Biology, ex Chef de Service, Centre de lutte contre le Cancer, Lyon, France - Vin Tangpricha MD, PhD, Associate Professor of Medicine, Emory University, Atlanta, GA

    - Jean-Paul Viard, MD, PhD, Praticien Hospitalier, Centre de Diagnostic et de Thérapeutique Unité fonctionnelle de Thérapeutique en Immuno-infectiologie (T2i), Hôtel-Dieu, Paris, France

    - Susan J. Whiting, PhD, Professor of Nutrition, College of Pharmacy and Nutrition, University of Saskatchewan, Canada

    - Armin Zittermann, MD, Department of Cardio-thoracic Surgery, Heart Center North Rhine-Westfalia, Rhur University Bochum, Germany