Phosphates Possibly Linked to Lung Cancer Risk

A diet rich in phosphate accelerated the growth of lung cancers in mice and may increase the risk of tumors in those predisposed to the disease, a preliminary study reports. 

Phosphate is found in many natural foods, such as meats, fruits and leafy vegetables. Although phosphates are essential nutrients, dietary intake has significantly increased over the years. They are increasingly used as food additives in processed foods, such as baking powder, meats, sausages, cheeses and sodas. Phosphate helps increase shelf life, improves taste and texture and helps retain water in meats.

The researchers studied two groups of mice. One group was genetically predisposed to develop lung cancer, while the other had induced lung cancers. The mice ate a diet containing 0.5 percent phosphate (normal) or one percent phosphate (high) for four weeks and were monitored for the development of lung cancer. At the end of the study, the mice that received high amounts of phosphates had larger tumors that progressed faster than those receiving normal amounts of phosphates. According to the authors, phosphates may activate a pathway that promotes the growth of lung tumors.

However, because the study was performed in mice, it is unclear if the same effects would occur in humans. In addition, lung cancer is considered a multifactorial disease because several factors (such as smoking) are involved. Therefore, additional studies are warranted in this area.

For more information about phosphates, please visit Natural Standard's Foods, Herbs & Supplements database.

Comments

[Jake]

This is very interesting. However, since the study was not conducted in humans, we cannot assume that phosphate has the same effect in humans. I also feel it would be unethical to conduct this in human subjects if trials from mice show that high levels of phosphate may induce lung cancer. This study may also scare people away from getting their recommended daily intake of meats, fruits and vegetables. It would be helpful to know how much phosphorus is contained in each serving of the above so that people know how much intake could potentially be harmful.

[RZD]

WOW! That's crazy. How is a person supposed to keep track of the amount of phosphate consumed? This is very interesting, yet quite troubling.

[Luce]

I know phosphate is highly needed for DNA repair, so does this imply too much could actually be problematic during a repair process?

[M.F.]

I wonder how much phosphate we ingest every day with a well-balanced diet. Sometimes findings from studies can cause such an alarm, but you come to find out that they were giving the mice a mega dose of a substance, and we would never ingest that much.

[DL]

While interesting, it seems a bit early to start ringing alarm bells about phosphate intake. Mouse studies with arbitrary of dosages of “low” and “high” levels of dietary phosphate intake are all well and good but not yet the basis for lifestyle recommendations. Since phosphorous is prevalent throughout the body and involved in a multitude of normal metabolic processes, it’s unclear how and why phosphates might be involved in any carcinogenic processes and whether limiting phosphate intake would be effective or even recommended in reducing cancer risks.

[Luce]

I agree with M.F. We, as humans, could never ingest that much of phosphate. But to be on the safe side, we should try to maintain a balance intake without exceeding what the body needs or how much is actually needed.

[Gary]

I think this study is another example of why processed foods should be avoided. When phosphates and other ingredients are added to make foods have longer shelf lives, it disrupts the natural processes of the body and ends up over loading it with things we don't need. Maybe the carcinogenic effects seen in this study are a result of that.

[RZD]

Dr. Cho, a researcher on this topic, suggested that dietary regulation of inorganic phosphates may be critical for lung cancer treatment as well as prevention. Of course, if you are eating a diet high in vegetables and fruits and low in processed foods, you do not need to know why exactly the processed foods are bad for you. Whether this study has identified a real reason to avoid processed foods or not, we already know that drinking colas or other sodas isn't good for us and neither is eating processed cheese spreads.

[VLN]

I wonder if this information is being applied to patients with lung cancer. Have they thought of putting these patients on a strict diet that limits the amount of phosphate they consume? It would be interesting if they did a study on patients with lung cancer and controlled their phosphate intake to see how much it affects the progression of the cancer.

[Luce]

VLN,

That is a good point and possible approach that could be used in the treatment of lung cancer.

[Stacey]

VLN:

Yes, that would be a good study -- to monitor the phosphate intake of lung cancer patients. Perhaps those who consume large amounts of phosphates would be more at risk for lung cancer? Altough much more research would be needed to determine this factor in humans, I think. Still, it's a good idea to try to avoid those foods that are heavily processed for many reasons, salt intake for one.

[Kristy]

Are patients diagnosed with lung cancer supposed to follow a phosphate-restricted diet?

[Gary]

I think that everything could be harmful if not taken in moderation. Phosphate is found in so many things that we could never just stop ingesting it. If a person has more risk factors of developing lung cancer then they should look into phosphate. But for the general public, I don't think they should be scared of ingesting phosphate.

[Katie]

This study looked at mice with induced lung cancers and those who were predisposed to lung cancers...what about those who were not predisposed to lung cancers, who probably make up a large portion of the population?

[JBT]

This is very intriguing; however, like other people commented already, it is too early to come to any conclusions. The study was performed in mice, and as far as we know, the "high" amounts of phosphate that they refer to may be 20 times what we normally obtain from our diets. The study definitely does warrant further research though!

[KB]

Correct me if I am wrong, but do we really need to be worried about lung cancer and phosphate levels? I am pretty sure smoking is the problem here. Besides, although researchers only used 0.5% and doubled it for the second group of mice, that is 100% more than the first normal group of mice and may be slightly excessive. Too much of anything is probably bad for you. Also, mice do not equal people.

[Wayne]

I agree with KB and the other comments posted above that it seems too early to make a definitive conclusion from this. What is the proposed mechanism of action of dietary phosphate on the progression of lung disease? Also, if a cause-and-effect relationship can be established between high phosphate and lung disease, how can we use this information in a practical setting? I agree with the other comments posted earlier that it may be difficult to avoid many foods that contain phosphate, making this a difficult, yet intriguing topic.

[MHD]

It would be interesting to assess whether it is indeed phosphates in general that cause an increased risk for cancer or if it is a particular food with phosphates that causes the risk. The reason why I pose this question is because it may be questionable whether it is actually processed foods that are the culprit in this dilemma. I previously read a study that concluded that an increase in esophageal adenocarcinoma risk is highest in people who consume a large amount of processed meat, i.e. deli meats, sausages, etc. To say phosphates are in natural foods is one thing, but there needs to be clarification about what is done to that natural food during production.

[Jenn]

In response to Luce’s comment above, recommended dietary allowances (RDA) for phosphate daily in adults is 700mg. RDAs are, however, higher in children and pregnant women due to the higher calcium requirement.

One thing to point out in this study is that the researchers used “a diet containing 0.5 percent phosphate (normal) or one percent phosphate (high).” I find this measurement very ambiguous. Is it 0.5% of the total daily vitamin intake of the mice? Or what is this 0.5-1% based on?

Also, a normal American diet is usually high in phosphate and low in calcium due to higher consumption of processed foods. This can exacerbate/speed up bone loss. Therefore, I think it’s important for people to realize they’d need more calcium to prevent bone loss to go along with these high phosphate diets.

[John Murdock]

Every day, more and more products/chemicals are found to have a link to an increased prevalence of cancer in one form or another. The one thing that most of these have in common is the fact that they are man-made entities being utilized for another purpose than their natural intended ones. Food additives and preservatives are undoubtedly the cause for numerous cancers and health problems. When a product is having its “shelf-life” lengthened by the addition of another substance, it most likely will not go without consequence. We are taking certain products that normally would not exist for a specific length of time and artificially altering that. We must understand that humans existed for thousands of years without even a fraction of the documented cases of cancer society experiences today. The reason for this is our manipulation if natural order of existence.

[Brian]

Lung cancer is the most dangerous form of cancer globally, and it is responsible for more than three million deaths per year. The major risk factors associated with the risk of lung cancer are smoking, gender, radon gas, asbestos and other chemicals, race and heredity. It is very important to quit smoking because it is the single most important action to decrease the chances of getting lung cancer.

Since this is a new preliminary study, more studies are needed before a link between phosphate and luck cancer can be established.