Gladys Block

Education and career

Block received a Bachelor of Arts in English, Philosophy, and French from Swarthmore College in 1960, and a Ph.D. in epidemiology from Johns Hopkins University's School of Public Health in 1982.

From May 1982 to June 1991, Block worked at the National Cancer Institute of the National Institutes of Health as a nutritional epidemiologist. While there, she worked on the Block FFQ and conducted research on the role of Vitamin C and cancer risk.

From July 1991 onward, Block worked at the University of California, Berkeley as a professor (and subsequently professor emerita) of Community Health and Human Development in the School of Public Health.

In 1994, Block founded NutritionQuest, a company that provides diet and physical activity screeners including the Block FFQ, and provides the Alive! tool to help people improve their physical activity and food habits. Block is currently Senior Scientist at NutritionQuest.

Block FFQ

During her time at the National Cancer Institute (1982 to 1991), Block developed a semi-quantitative food frequency questionnaire (FFQ) that would later come to be known as the Block FFQ. The approach to questionnaire design was first described in a paper co-authored with Hartman, Dresser, Carroll, Gannon, and Gardner in 1986. Research by Block, Potosky, and Clifford on validation of the questionnaire was published in 1990.

After leaving the National Cancer Institute in 1991, Block continued to work on the FFQ, offering it through the company, NutritionQuest, that she founded in 1994. Subsequent released versions include the Block 95 and Block 98 FFQs. A web version was also released and validated.

The Block FFQ has been used in third-party research and has also been the subject of validation and comparison studies.

The Block FFQ is the earliest of the currently widely used FFQs in the United States. Other semi-quantitative FFQs include the Diet History Questionnaire (DHQ) and NHANES (also developed at the National Cancer Institute) and the Harvard FFQ, developed by a team at Harvard University led by Walter Willett.

The Block FFQ is currently offered by NutritionQuest at $2 per response.

The link between diet, Vitamin C (and other nutrients) and health status (particularly cancer risk)

While at the NCI, Block led research on the nutritional effects of the consumption of Vitamin C on health status and in particular cancer risk. In a three-day symposium at the National Institutes of Health (September 10 to 12, 1990), Block summarized existing research on the role of Vitamin C in cancer prevention as follows: "Of 46 reports on epidemiologic studies, 33 described significant protective effects on cancer mortality or incidence." In 1992, Block's review of 15 epidemiological studies on cancer rates and intake of Vitamin C was cited in the New York Times.

Block continued to study the effect of vitamin and other nutrient consumption on health status while at the University of California, Berkeley. Her research results have generally supported the idea that vitamin consumption reduces the risk of adverse health conditions such as cancer, diabetes, and hypertension, and that dietary supplements can be an effective source of vitamins (albeit not as good as direct consumption of fruits and vegetables containing the relevant nutrients).

Block's findings on the relation between Vitamin C, diet patterns (including consumption of fruits and vegetables as well as dietary supplements), and cancer have been cited in popular press pieces including in the New York Times.

Block has been cited in media coverage of the debate around the efficacy of dietary multivitamin supplements in combating health risks including the risk of cancer, obesity, diabetes, heart disease, and hypertension. Others taking a similar position as Block (in favor of dietary supplements) include Harvard professor Walter Willett (designer of the Harvard FFQ), researcher Bruce N. Ames, and Michael Jacobson of the Center for Science in the Public Interest. Those on the other side include Marion Nestle, Joan Gussow, Catherine Wotecki, Walter Mertz, and Edgar Miller.

ALIVE program to improve diet and physical activity

Block has developed a program called ALIVE that people can use to improve their diet and physical activity. The program and its spinoff, ALIVE-PD (to help prediabetics prevent diabetes) are currently offered through Turnaround Health, a division of NutritionQuest.

Variety in diet

Block has led research on the variety in people's diet and its effects on people's nutrient consumption and health status. She has been cited on the subject in the New York Times.