It was wartime and food was scarce. Leaders of England’s effort to wage war and help the public survive during World War II needed to know: Were the rations in lifeboats adequate for survival at sea? And, among several experiments important for public as well as military heath, how much vitamin C did a person need to avoid the deadly disease scurvy?

In one experiment at the in Sheffield, called the volunteers were fed only what the navy carried in lifeboats. The grueling experiment resulted in more water and less food being carried in lifeboats.

One of the more robust experiments run on human subjects during this time in England, which has had long-lasting public health consequences, was a started in 1944, also at Sorby. This medical experiment involved 20 subjects, most of whom were conscientious objectors living in the building where many experiments, including the shipwreck experiment, were conducted. They were overseen by , and detailed data was kept on each participant in the study.

“The vitamin C experiment is a shocking study,” said , lead author of  of the Sorby vitamin C experiment, a practicing dentist and professor of oral health sciences in the UW School of Dentistry. “They depleted people’s vitamin C levels long-term and created life-threatening emergencies. It would never fly now.”

Even though two trial participants developed life-threatening heart problems because of the vitamin C depletion, Hujoel added, none of the subjects were permanently harmed, and in later interviews several participants said they would volunteer again given the importance of the research.

Because of the war and food shortages, there was not enough vitamin C available, and they wanted to be conservative with the supplies, explained Hujoel, who is also an adjunct professor of epidemiology. The goal of the Sorby investigators was not to determine the required vitamin C intake for optimal health; it was to find out the minimum vitamin C requirements for preventing scurvy.

Vitamin C is an important element in your body’s ability to heal wounds because the creation of scar tissue depends on the collagen protein, and the production of collagen depends on vitamin C. In addition to knitting skin back together, collagen also maintains the integrity of blood vessel walls, thus protecting against stroke and heart disease.

In the Sorby trial, researchers assigned participants to zero, 10 or 70 milligrams a day for an average of nine months. The depleted subjects were then repleted and saturated with vitamin C. Experimental wounds were made during this depletion and repletion. The investigators used the scar strength of experimental wounds as a measure of adequate vitamin C levels since poor wound healing, in addition to such conditions as bleeding gums, are an indication of scurvy.

In the end, the Sorby researchers said 10 milligrams a day was enough to ward off signs of scurvy. Partly based on these findings, the WHO recommends 45 milligrams a day. Hujoel said that the findings of the re-analyses of the Sorby data suggest that the WHO’s recommendation is too low to prevent weak scar strength.

In a bit of scientific detective work, Hujoel said he tracked down and reviewed the study’s data, and with the aid of , a scientist with Brigham and Women’s Hospital/Harvard Medical School, put the data through modern statistical techniques designed to handle small sample sizes, techniques not available to the original scientists. The results of their work were .

The Hujoels discovered that the data from this unique study — which has been a cornerstone used by WHO and other agencies for establishing healthy levels of vitamin C in humans — needed more than an “eyeball method” of data assessment.

“It is concluded that the failure to reevaluate the data of a landmark trial with novel statistical methods as they became available may have led to a misleading narrative on the vitamin C needs for the prevention and treatment of collagen-related pathologies,” the researchers wrote.

“Robust parametric analyses of the (Sorby) trial data reveal that an average daily vitamin C intake of 95 mg is required to prevent weak scar strength for 97.5% of the population. Such a vitamin C intake is more than double the daily 45 mg vitamin C intake recommended by the WHO but is consistent with the writing panels for the National Academy of Medicine and (other) countries,” they add.

The Hujoels’ study also found that recovery from a vitamin C deficiency takes a long time and requires higher levels of vitamin C. Even an average daily dose of 90 milligrams a day of vitamin C for six months failed to restore normal scar strength for the depleted study participants.

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For more information, contact Philippe Hujoel at hujoel@uw.edu.

Current advice from the tells you that if your gums bleed, make sure you are brushing and flossing twice a day because it could be a sign of gingivitis, an early stage of periodontal disease. And that might be true. So if you are concerned, see your dentist. However, a new ����Ӱ�Ӵ�ý study suggests you should also check your intake of vitamin C.

“When you see your gums bleed, the first thing you should think about is not, I should brush more. You should try to figure out why your gums are bleeding. And vitamin C deficiency is one possible reason,” said the study’s lead author , a practicing dentist and professor of oral health sciences in the UW School of Dentistry.

Hujoel’s study, , analyzed published studies of 15 clinical trials in six countries, involving 1,140 predominantly healthy participants, and data from 8,210 U.S. residents surveyed in the Centers for Disease Control and Prevention’s Health and Nutrition Examination Survey. The results showed that bleeding of the gums on gentle probing, or gingival bleeding tendency, and also bleeding in the eye, or retinal hemorrhaging, were associated with low vitamin C levels in the bloodstream. And, the researchers found that increasing daily intake of vitamin C in those people with low vitamin C plasma levels helped to reverse these bleeding issues.

Of potential relevance, says Hujoel, who is also an adjunct professor of epidemiology in the UW School of Public Health, both a gum bleeding tendency and retinal bleeding could be a sign of general trouble in one’s microvascular system, of a microvascular bleeding tendency in the brain, heart and kidneys.

The study does not imply that successful reversing of an increased gingival bleeding tendency with vitamin C will prevent strokes or other serious health outcomes, Hujoel stresses. However, the results do suggest that vitamin C recommendations designed primarily to protect against scurvy — a deadly disease caused by extremely low vitamin C levels — are too low, and that such a low vitamin C intake can lead to a bleeding tendency, which should not be treated with dental floss.

Consequently, Hujoel does recommend people attempt to keep an eye on their vitamin C intake through incorporation of non-processed foods such as kale, peppers or kiwis into your diet, and if you can’t find palatable foods rich in vitamin C to consider a supplement of about 100 to 200 milligrams a day.

If someone is on a specialized diet, such as a paleo diet, it’s important that they take a look at their vitamin C intake, Hujoel said. “Vitamin C-rich fruits such as kiwis or oranges are rich in sugar and thus typically eliminated from a low-carb diet.”

This avoidance may lead to a vitamin C intake that is too low and is associated with an increased bleeding tendency. People who exclusively eat lean meats and avoid offal, the vitamin-rich organ meats, may be at a particularly high risk for a low vitamin C intake.

The association between gum bleeding and vitamin C levels was recognized more than 30 years ago. In fact, two studies co-authored by former dean of the UW School of Dentistry Paul Robertson (published in and ) identified gum bleeding as a biological marker for vitamin C levels.

However, this connection somehow got lost in dental conversations around bleeding gums.

“There was a time in the past when gingival bleeding was more generally considered to be a potential marker for a lack of vitamin C. But over time, that’s been drowned out or marginalized by this overattention to treating the symptom of bleeding with brushing or flossing, rather than treating the cause,” Hujoel said.

Hujoel’s literature review also determined that “retinal hemorrhaging and cerebral strokes are associated with increased gingival bleeding tendency, and that (vitamin C) supplementation reverses the retinal bleeding associated with low (vitamin C) plasma levels.”

So, missing the possible connection between gum bleeding and low levels of vitamin C has the potential to have serious health consequences.

The study authors write: “A default prescription of oral hygiene and other periodontal interventions to ‘treat’ microvascular pathologies, even if partially effective in reversing gingival bleeding as suggested in this meta-analysis, is risky because it does not address any potential morbidity and mortality associated with the systemic microvascular-related pathologies.”

Co-authors include Tomotaka Kato, Department of Oral Health Sciences, UW School of Dentistry; Isabel Hujoel, Division of Gastroenterology and Hepatology, Mayo Clinic; and Margaux L.A. Hujoel, Department of Biostatistics, Harvard T.H. Chan School of Public Health.

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For more information, contact Hujoel at hujoel@uw.edu.

The results provide further insight into the development of complex brain functions which ultimately determine which side of the batter box the infant likely will choose.

“We think breastfeeding optimizes the process the brain undergoes when solidifying handedness,” said , the study’s author, a professor at the UW’s School of Dentistry and an adjunct professor of epidemiology at the School of Public Health. “That’s important because it provides an independent line of evidence that breastfeeding may need to last six to nine months.”

The study does not imply, however, that breastfeeding leads to right-handedness, Hujoel said. Handedness, whether it be right- or left-handed, is set early in fetal life and is at least partially determined by genetics. The research does sheds light on when the region of the brain that controls handedness localizes to one side of the brain, a process known as brain lateralization. Possibly, the research shows, breastfeeding optimizes this lateralization towards becoming right- or left-handed.

The findings were published online last month in the journal .

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