By Gene Bishop

One of my greatest satisfactions as a physician was the ability to get to know many people from all over Philadelphia, and to offer advice and support as they tried to care for themselves and their families.

I considered being a primary-care physician a great privilege, supporting people in times of need, finding the right medicine for asthma or hypertension, encouraging those who struggled with diet and diabetes.

But at the same time, one of my greatest frustrations was the inability to write a prescription for the conditions that promote health and well-being: safe, clean housing, healthy food at affordable prices, places to exercise that are free from danger, and an education system that works.

I knew that the health inequities in our city come not from the failure of doctors and hospitals to provide equal treatment, but primarily from the lack of access to resources such as lead-free housing, schools with libraries, sufficient and healthy food, and accessible employment. I had no way to write a prescription for those resources and send it electronically to be fulfilled by others. However, Mayor Kenney's proposed soda tax offers me an opportunity to write that prescription.

As important as it is for people to be able to see a doctor or nurse when they are ill, there are factors much more important than a visit with me.

Donald Schwarz, a former city health commissioner, once said that the most important thing that could be achieved for the health of Philadelphia children was for every child to be reading at grade level by third grade. We're not there.

I saw more and more people with diabetes over the years. It is a costly disease, for those who have it and for the city and country. But advising my patients to limit soda consumption had limited impact compared with the $1 million a day in soft-drink advertising aimed at children. The amount of money Big Soda spends per year to advertise just to children ($365 million) would pay for six years of pre-K for the children of Philadelphia.

And I felt particularly hampered in Philadelphia because studies have shown that black children and teens see more than twice as many ads for sugary drinks and energy drinks on TV as white children do. Advertising for similar drinks on Spanish-language TV increased by 44 percent in the last few years.

I was too busy to maintain active Facebook, Twitter, or Instagram accounts, but Coca-Cola claims to have more than 18,000 Instagram followers. That is totally free advertising. What could my tweet do? As Philadelphia medical institutions reach out to the African American and Spanish-speaking communities to narrow life expectancy gaps, Big Soda is reaching out to those communities pushing products that have the opposite effect.

Every physician must consider what problems can be solved by individual interventions with patients and what problems need bigger solutions. In my own experience during 30 years in practice, I saw numerous individual health problems become public-health issues.

We no longer think that a woman who is beaten by her husband has an individual problem. The abuser has committed a crime, and the legal system is a large part of the solution.

Seat belts and child safety seats are no longer an individual health choice. They have been proven to save so many lives that they are a public-health and legal priority.

I believe we must make the same transition in regard to diabetes and excess weight. They are no longer just individual problems but public-health issues for the city and country. There are many steps involved in that transition, but now, in Philadelphia, we have an opportunity to take one step.

Many of my patients with diabetes would be relieved to know they have the support of community policy in struggling with the illness. We are a critical test case for the soda industry, which does not want to lose for fear of a tax epidemic spreading to other cities. But we are also a critical test case for the health of our city.

Medical decisions always weigh benefits and risks. We can make a decision that we value education, parks, recreation centers, and libraries, and that this tax will benefit our entire city - including low-income communities - more than it will harm us.

Supporting the soda tax lets me write a meaningful prescription that would take two actions at once: improving both individual health and the health of our communities.

I know there are no miracle drugs - every medication has benefits and side effects. In this situation, however, the benefits outweigh the side effects. Let's all send our prescriptions to the "City Council Pharmacy" and ask its members to fill it promptly by enacting the soda tax.

Gene Bishop is a retired primary-care physician from Philadelphia and a clinical associate professor of medicine at the Perelman School of Medicine of the University of Pennsylvania.