Stormy echoes of the
1918 "Spanish" flu pandemic
The 1918 flu — which likely came from chickens or other birds — first appeared among soldiers at Fort Riley, Kansas.
They carried the virus on their way to Europe during World War I, and back again, which led Americans to mistakenly — but perhaps conveniently — calling it the Spanish flu.
Ironically, greater percentages of children and the elderly survived the deadly 1918 "Spanish" flu pandemic, probably because their immune systems — which were respectively immature and age-weakened — couldn't mount a counterproductive cytokine storm, or only relatively weak, survivable storms, and/or because they'd previously been exposed and acquired resistance to a similar virus.
Conversely, the 1918 flu pandemic killed higher proportions of younger, healthy people than do typical flu viruses, because the cytokine storm unleashed by their robust immune systems caused raging inflammation and filled their lungs with fluid.
The authors of that BMJ evidence review also confirmed that vitamin D can help curb the potentially deadly “cytokine storm” immune-system overreaction that triggers wildly excessive inflammation and fills a patient’s lungs with fluid: see Vitamin D Lack May Promote Sickening Inflammation.
Evidence review made a compelling case that lack of the “sunshine vitamin” enables the flu — and other lung-focused viruses
A compelling scientific paper offers a persuasive explanation for the generally seasonal nature of the flu.
Influenza infections sweep the Northern Hemisphere during the winter months and usually peak in America, Canada, and Europe between late December and March.
None of the numerous theories floated to explain the seasonal flu spike — from the flood of frigid air to the wintertime tendency of people to huddle indoors — fully passes the scientific-credibility test.
Dr. Scott Dowell is director of the Global Disease Protection Program at the Centers for Disease Control and Prevention. In a recent interview in LOHAS journal he called the conventional explanations “… astonishingly superficial and full of inconsistencies.”
Dr. Dowell and others find merit in a provocative new hypothesis: one that attributes the winter-focused nature of flu epidemics in the northern third of the globe to the season's obvious shortage of vitamin-D-generating sunshine.
Why would vitamin D help protect against the flu? It plays a key role in the body's immune-system defense against infection, especially in the lungs, where flu and corona viruses tend to settle.
Influenza kills an average 36,000 people in the U.S. every winter. As Dowell said, should the new hypothesis prove true, “…the potential impact would be far greater than the current influenza vaccine.”
Paper's authors offer radically different view of the flu
The authors of the new  evidence review included leading vitamin D researchers Michael C. Holick of Boston University and Edward Giovanucci of Harvard University, as well as Commander John C. Umhau, MD, MPH, CPE of the United States Public Health Service.
Many mysteries surround the seasonal nature of influenza, and the simultaneous occurrence of local epidemics in widely separate regions: characteristics that make it hard to explain influenza epidemics as typical person-to-person viral infections, like the common cold or measles.
The study's authors make a strong case that the mystery factor behind the seasonal rise in flu rates in the winter is a lack of sunshine-generated vitamin D.
If they're right, high doses of supplemental vitamin D could provide a safe, effective, natural remedy for garden variety flu, and could even help prevent and treat far more dangerous forms, such as the flu virus that killed an estimated 50-100 million people worldwide in 1918.
The new hypothesis holds that the various flu viruses lie dormant in people and emerge during the dimmer days of winter in northerly climes and during the rainy seasons in tropical regions: especially in people whose darker skin color — or sun avoidance or heavy sunscreen use — leaves them very low in vitamin D.
For example, studies ranging from Malaysia and South India to China and Japan show that women there have surprisingly low levels of vitamin D, especially in their winter months.
Researchers attribute the lack of vitamin D in these Asian nations in part to women's indoor careers and a cultural preference for pale skin that leads them to use clothes, parasols, and sunscreens to avoid tanning. (This unhealthful prejudice is common among East and South Asian women, where skin-lightening creams are increasingly popular.)
The US recommended daily allowance (RDA) for vitamin D is 400 international units (IU) — and on sunny days, a fair-skinned person generates the equivalent of 20,000 international units (IU) in just 15-20 minutes. In contrast, one cup of fortified milk contains fewer than 100 IU.
Most vitamin D researchers agree that people should take at least 1,000 IU per day, rather than the US RDA of only 400 IU. [Editor's Note: Since we published the original article in 2006, the RDA for vitamin D from early childhood through old age has been raised to 600 IUs.] And most experts urge older, heavier, and dark-skinned people — who make and absorb less vitamin D — to take 3-5,000 IU every day.
Excerpts from “Epidemic influenza and vitamin D”
The following quotes come directly from the authors' summary of their findings and conclusions. (We've added some clarifications in brackets [ ].) Note: E.R. Hope-Simpson, M.D. is the British doctor who conducted pioneering research that undermined conventional wisdom concerning the causes of flu outbreaks:
British country doctor challenged conventional wisdom
Dr. John J. Cannell, one of the authors of the provocative new review, highlighted the pioneering work of Dr. Hope-Simpson in a recent edition of his vitamin D newsletter.
Hope-Simpson, who died in 2003 at the age of 95, marshaled his maverick research on influenza in a 1992 book titled “The Transmission of Epidemic Influenza.”
In his essay, Dr. Cannell summarized some of Dr. Hope-Simpson's cogent but inconvenient observations as follows (key points underlined for emphasis):
We'll have to await the results of controlled clinical studies to know whether vitamin D really fights the flu.
But leading vitamin D researchers believe that it makes good sense to take ample daily doses of vitamin D (i.e., 2-4,000 IU) to help prevent cancer and osteoporosis, and the authors of the new paper say it can't hurt to start taking take larger doses temporarily if you feel a flu coming on.
While vitamin D can be toxic if taken in very large doses over a period of weeks or months, all of the available evidence indicates that it is safe to take daily doses that are at least several times higher than the US government's established safe upper level dose (Vieth 1999, 2001, 2006).
The official US safe maximum intakes of vitamin D are 1,000 to 1,500 IU/day for infants, 2,500 to 3,000 IU/day for children aged 1-8 years, and 4,000 IU/day for children aged nine years and older, adults, and pregnant and lactating teens and women.
Authors propose preventive and therapeutic use of vitamin D
In their new paper, some of American's preeminent vitamin D researchers went beyond hypothesizing to recommend prudent anti-flu use of vitamin D.
Dr. Cannell noted the hypothetical nature of his team's findings, saying “Like all theories, our theory must withstand attempts to be disproved with dispassionately conducted and well-controlled scientific experiments.”
But their research certainly suggests the possibility of some immediate practical implications:
Newsweek provides forum for vitamin D pitch
Meir Stampfer, M.D., chair of the epidemiology department at the Harvard School of Public Health, wrote a column in last week's  issue of Newsweek magazine, in which he decried the vitamin D deficiencies common among Americans.
These were some of his arguments for raising the public profile of vitamin D, to ensure that Americans to get much more of it via foods and supplements:
To view all of our vitamin D articles, search our website for “vitamin D”. And stay tuned … we'll keep you posted on developments regarding vitamin D and human health.