Time to open up the EWG mailbag and respond to some questions from our community. We'd love to hear from you. If you have any questions for our scientists you can submit them here.
Please note: EWG can't provide any medical advice. If you're worried that you may be sick please consult your physician or another medical professional.
Questions may be edited for clarity and brevity.
What are some less commonly known dietary tips to prevent cancer?
--Michelle G.
The best advice is really the most straightforward. Shift to a diet that focuses on plant-based foods, don't overeat, stay physically active and maintain a healthy weight. The hard part is achieving those goals.
There is no "superfood" that is going to prevent cancer on its own. Those things can be part of a healthy diet, but they are not a panacea. And supplements, unless you have a specific nutrient deficiency, could actually do harm.
It's not exciting news, but probably the best place to start is setting a diet that focuses on plant-based foods. Citrus fruits, dark green leafy vegetables and cruciferous vegetables, just to name a few, have been linked to reduced cancer risks and other health benefits. Eating a diversity of fruits and vegetables provides a variety of nutrients and helps to maintain a healthy body weight, as these are not calorie-dense foods.
It's also a good idea to limit the amount of heavily processed foods you consume, or at least be picky about the ones you choose. They can be loaded with sugar, salt and trans fats. In addition, certain additives and packaging materials containing BPA, parabens or phthalates could act as obesogens. These chemicals may promote excess body fat, which in turn can affect hormone and growth factor levels, and decrease the amounts of certain nutrients circulating in the body.
We should also be introducing children to healthy foods because our food preferences can begin to form early in life. Less then 10 percent of children are eating the recommended amounts of vegetables, and the vegetables they consume most often are fried potatoes. It's no wonder so many people have unhealthy eating habits.
Any leads on what causes Non Hodgkin's lymphoma?
--Lin G.
Non-Hodgkin's lymphoma (NHL) is a complex disease, or rather, set of diseases that affect the cells of our immune system – specifically B-cells, T-cells and natural killer cells (all types of white blood cells known as lymphocytes). These cancers are closely related, but because they originate in different cells they can have distinct etiologies – what causes one type of lymphoma may not cause another. This can make identifying risk factors difficult because certain subtypes of NHL are less common than others and are thus harder to study.
Still, several risk factors linked to one or more types of NHL have been identified. The strongest are related to disruptions to the immune system. Immune disorders, HIV/AIDS and even immunosuppressive drugs used during organ transplants have been linked to multiple types of NHL.
Certain infections, such as Epstein Barr virus (responsible for mono) and hepatitis C, may be risks. Autoimmune diseases have been linked to several types of NHL, but allergies may decrease risk.
A host of occupational, environmental and lifestyle factors have also been linked to NHL risk. Certain pesticides, including glyphosate and 2,4-D, have been linked to some forms of NHL. Exposure to PCBs can increase the risk of NHL, for T-cells in particular, as can exposure to industrial solvents like TCE. Historically, use of hair dyes is also a risk factor, although risks from current formulations haven't been observed.
Increased risks have been found among farmers, painters and possibly even those in woodworking and electrical industries, suggesting there are concerning exposures associated with these jobs.
Surprisingly, smoking is not a strong risk factor for NHL. Obesity and heterocyclic amines, which are formed in charred meats, are risk factors. Some odder risks are observed with later birth order – perhaps due to earlier exposure to infections – and darker eye color due to sunlight sensitivity.
I know keeping food in plastic is not a good idea. Is it only if the plastic is heated up or would storing something like pretzels in a plastic container contaminate the food, too?
--Connie B.
I love this new product Fair Life milk and so do my kids, but the packaging is a #7 PETE plastic bottle and my mama gut is telling me that may not be so good for us ... anything you can say about risk of this packaging to our health
--Sarah N.
I warmed up some potatoes for a party in a plastic bowl that started to get soft and melt in the microwave. I'm wondering if I put people at risk. Can a one-time exposure put people at risk for cancer or other problems?
--M B.
Not all plastics are equal in terms of health concerns. In general, EWG recommends avoiding plastics labeled #3 (PVC) and #7 (PC) because they can contain and leach phthalates and BPA. Plastics labeled #7 are a bit of an unknown because this is an "other" category. The plastic in question may contain BPA or other substances of concern – or it may not.
The thing to keep in mind though is that it's not just the type of plastic, but how the plastic is used. Heat has shown to be the biggest factor in the leaching of BPA. Leaching of chemicals from plastics can also increase with wear and tear, repeated washings, and storing liquids or foods that are acidic or basic. Milk is stored cold and is close to a neutral pH, which lessens, but doesn't eliminate, the possibility of BPA leaching if it's contained in this particular #7 plastic. And we don't have information available as to whether or not BPA would be at concerning levels. I would be less concerned about storing pretzels or similar foods in plastic, provided the containers are in good condition.
A one-time exposure is unlikely to be cause for concern. Repeated, long-term exposures are most dangerous because they allow chemicals to begin disrupting our hormone systems or break down our bodies' defenses.
I was diagnosed with Stage II Grade 3 Invasive Ductal Carcinoma in June. I am only 36. In my town, water has been contaminated with triah-something. My 35-year-old co-worker was also diagnosed with breast cancer weeks prior to my diagnosis. We live and work within a three-mile radius. This seems very coincidental to me. Is there any link between the quality of water report and breast cancer? I was told there is only a 0.4 percent chance anyone our age would get breast cancer.
--Megann W.
Recently, I was diagnosed with breast cancer at age 49. There isn't a genetic link in either side of our family. I'm trying to figure out what caused this cancer. What things in diet and in the environment would you eliminate (or proceed with caution)?
--Jill H.
First, I want to wish you all the best in getting well.
Breast cancer is largely a disease of hormonal origin, namely factors that prolong estrogen exposure throughout life. Consequently, the timing of certain exposures and events during our lifetimes can be very important.
Regular physical activity and a healthy body weight are especially important after menopause because body fat can contribute to the generation of estrogen at a time when levels should be declining. Conversely, exposures to radiation and certain chemicals may be most damaging during early life and in utero. Chemicals like dioxins can increase the susceptibility to other carcinogens later in life.
PCBs have been linked to breast cancer. And in general, endocrine disrupting chemicals are of concern because they can mimic or interfere with hormones in the body. EWG has a list of some common ones with tips on how to avoid them.
Postmenopausal hormone replacement therapy is one of the biggest risk factors because it prolongs estrogen and progesterone exposure, which is why it's a treatment that should be carefully discussed with your doctor. Early age of puberty is an example of a risk that may be related to our environment in ways we don't fully understand yet.
Diet doesn't seem to have as strong of an impact for breast cancer as hormonal factors. But that's not to say diet has no effect on risk. Alcohol consumption, especially during adolescence, can interfere with the action of estrogen and is the most well-established dietary risk factor. Red and processed meats, and high fat diets may also increase risk, but those associations are less clear. Fruits and vegetables, on the other hand, have been linked to lower risk of ER-breast cancers. In general, a diet that promotes a healthy body weight is key because body fat is an important risk.
How is iron a carcinogen?
--Usha R.
One of the paradoxes of life – something that is essential can also be harmful.
Iron easily binds with oxygen – think of how quickly iron metals rust. This quality makes iron useful for transporting oxygen around our body, which it does as the central part of the molecule hemoglobin. Iron is also a part of certain enzymes that play key roles in metabolism and cell growth. These properties of iron, namely its ability to give up electrons, also make it useful for generating DNA-damaging free radicals.
Iron, like other micronutrients, is only required in small amounts in our bodies. Too much, and iron can be stored and absorbed by our bodies in ways that allow it to be reactive in generating free radicals and subsequent tumor growth. This is why I would advise against dietary supplements unless you have a specific deficiency (which could very well be the case with iron).
Hello, I suffer from Vitiligo, where I have no melanin. What is the best SPF to use in order to not get burns?
--Harsha S.
I am confused over vitamin A for sunscreen. Is it something we have to avoid?
And I can't find the best sunscreen without concerning chemicals. What do you think?
--Yak Wan L.
Based on our research, going with SPF 30 to 50 is probably a good choice and you'll want one that offers broad-spectrum protection (look for ingredients 3% Avobenzone or >10% Zinc Oxide). Sunscreens above SPF 50 generally do not offer much, if any, increased protection from UV rays. The effectiveness of any sunscreen, no matter the SPF, depends on you applying and reapplying as directed. Keep in mind that your skin can be damaged without burning.
Finding shade, sunglasses, covering up and limiting your time in the sun when it's highest in the sky are other excellent ways to cut down on harmful UV exposure.
Vitamin A (also labeled retinyl palmitate or retinol) is an antioxidant. Small concentrations in your diet can be helpful. But dose is important. High levels of vitamin A, through high dose beta-carotene supplements, have been found to increase lung cancer risks among smokers.
Similarly, there are concerns when vitamin A is applied to the skin and exposed to sunlight. Animal studies have found vitamin A combined with UV exposure accelerated the development of skin tumors. That's why EWG recommends avoiding skincare products containing this ingredient.
We also recommend avoiding sunscreens containing the synthetic estrogen oxybenzone. You can use our sunscreen guide to find products that work for you.