If you saw the headlines last week, you may be wondering what’s up with calcium supplementation. Afterall, don’t medical professionals advise the use of supplements to stave off bone loss associated with osteoporosis? And as a result, the Centers for Disease Control reports that over 50% of adults currently use calcium supplements and more than 60% of women over age 60.
It’s important to get away from the sensational headline and take a closer look at what the research shows and what you need to know.
Previous studies have suggested that there may be a link between use of calcium supplements (without vitamin D) and heart attack; in fact, as Reuters‘ reported last year, calcium supplements were shown to increase the risk of heart attack by as much as 31%, possibly as a result of plaque formation in blood vessels. However, is the risk the same if calcium is used alone versus if it is used in conjunction with vitamin D? In the Women’s Health Initiative study, the use of calcium and vitamin D did not appear to influence heart disease risk at all.
However, researchers decided to take another look at the data because they say that in this trial, more than half of participants were taking ‘personal calcium’ (i.e. not regulated or standardized to all trial participants) and almost half were also adding Vitamin D.
In this reanalysis, published just last week in the British Medical Journal, the researchers discounted the women who were characterized as personal users of calcium supplements and instead, limited their evaluation to a group of women who were not using personal calcium supplements at the study’s start and previously unpublished data from the trial. The findings? The use of calcium with or without vitamin D appeared to cause a 25% to 30% increase in the risk for heart attack and a 15% to 20% increased risk for stroke. However, the researchers say that even small increases in the incidence in heart disease may manifest substantially, especially in the elderly. They add that if you take a look at the risk-benefit ratio, it is unfavourable, meaning that taking calcium with or without vitamin D for five years would cause twice as many heart attacks or strokes than then numbers of fractures that would be prevented. Additionally, the data analysis suggests that dosing is not a factor, and that the total amount of calcium taken daily is less important than the abrupt changes in blood calcium levels immediately following supplementation.
Although this research answers a few questions about potential risks about calcium supplementation, it also leaves a key question unanswered: how does the addition of magnesium and vitamin K, which are often included in commercially-available calcium supplements, affect these findings? Data suggest that these minerals and vitamins are added to keep calcium in the bones where it belongs and out the arteries where it does not.
The best guideline, as always, is to visit a physician to assess your bone health and come up with a plan that works specifically for you. Although calcium supplementation appears to be risky, more data are needed before leading organizations start to change their tune about calcium and bone health. Meanwhile, stay ahead of the headlines and try to focus on increasing the amount of calcium-rich foods in your diet:
|Yogurt, plain, low fat, 8 ounces||415||42|
|Sardines, canned in oil, with bones, 3 ounces||324||32|
|Cheddar cheese, 1.5 ounces||306||31|
|Milk, nonfat, 8 ounces||302||30|
|Milk, reduced-fat (2% milk fat), 8 ounces||297||30|
|Milk, lactose-reduced, 8 ounces**||285–302||29–30|
|Milk, whole (3.25% milk fat), 8 ounces||291||29|
|Milk, buttermilk, 8 ounces||285||29|
|Mozzarella, part skim, 1.5 ounces||275||28|
|Yogurt, fruit, low fat, 8 ounces||245–384||25–38|
|Orange juice, calcium-fortified, 6 ounces||200–260||20–26|
|Tofu, firm, made with calcium sulfate, ½ cup***||204||20|
|Salmon, pink, canned, solids with bone, 3 ounces||181||18|
|Pudding, chocolate, instant, made with 2% milk, ½ cup||153||15|
|Cottage cheese, 1% milk fat, 1 cup unpacked||138||14|
|Tofu, soft, made with calcium sulfate, ½ cup***||138||14|
|Spinach, cooked, ½ cup||120||12|
|Ready-to-eat cereal, calcium-fortified, 1 cup||100–1,000||10–100|
|Instant breakfast drink, various flavors and brands, powder prepared with water, 8 ounces||105–250||10–25|
|Frozen yogurt, vanilla, soft serve, ½ cup||103||10|
|Turnip greens, boiled, ½ cup||99||10|
|Kale, cooked, 1 cup||94||9|
|Kale, raw, 1 cup||90||9|
|Ice cream, vanilla, ½ cup||85||8.5|
|Soy beverage, calcium-fortified, 8 ounces||80–500||8–50|
|Chinese cabbage, raw, 1 cup||74||7|
|Tortilla, corn, ready-to-bake/fry, 1 medium||42||4|
|Tortilla, flour, ready-to-bake/fry, one 6″ diameter||37||4|
|Sour cream, reduced fat, cultured, 2 tablespoons||32||3|
|Bread, white, 1 ounce||31||3|
|Broccoli, raw, ½ cup||21||2|
|Bread, whole-wheat, 1 slice||20||2|
|Cheese, cream, regular, 1 tablespoon||12||1|
* DV = Daily Value. DVs were developed by the U.S. Food and Drug Administration to help consumers compare the nutrient contents among products within the context of a total daily diet. The DV for calcium is 1,000 mg for adults and children aged 4 years and older. Foods providing 20% of more of the DV are considered to be high sources of a nutrient, but foods providing lower percentages of the DV also contribute to a healthful diet. The U.S. Department of Agriculture’s Nutrient Database Web site lists the nutrient content of many foods. It also provides a comprehensive list of foods containing calcium.
** Calcium content varies slightly by fat content; the more fat, the less calcium the food contains.
*** Calcium content is for tofu processed with a calcium salt. Tofu processed with other salts does not provide significant amounts of calcium.
Any regular reader of this blog knows that I am not a fan of hormone replacement therapy (HRT) nor the health risks associated with it. Nevertheless, although I espouse alternative strategies for dealing with menopause, I do feel that sharing news about HRT is important; accurate information leads to informed and shared decisionmaking.
So, do they (i.e. hormones) or don’t they (cause harm)? Undoubtedly, important variables come into play, including current age, how close to menopause hormones are started, current health status, whether or not a woman has had a hysterectomy, smoking history, etc. Also important is whether estrogen is used alone or in combination with progesterone. And yet despite these factors, many medical organizations continue to recommend that HRT be used for the shortest time period possible if at all.
Still, researchers continue to delve into data from the now infamous Women’s Health Initiative Study to tease out the bad, ugly and even the good.
This week, they are reporting on over 7,600 women who had taken estrogen alone for approximately 6 years, had had prior hysterectomies and were followed for an average of 10 years after the trial ended. If you recall, there has been some controversy as to whether or not estrogen alone is safer than combined HRT and actually lowers the risk for breast cancer in particular, which is why these data are particularly intriguing.
The researchers report that age at the time that hormone therapy (in this case, estrogen alone) is started is important. In fact, women who started estrogen therapy in their 50s, an increased risk for stroke and embolism, which appeared while taking estrogen, actually disappeared in the years that followed. Unfortunately, so did protection against hip fracture. Moreover, earlier reports of a decline in breast cancer risk were upheld despite body mass indices. However, the researchers say that this finding in particular, runs contrary to the preponderance of evidence from the majority of observational studies which show that estrogen use increases the risk of breast cancer, especially in lean women and after a long time period of use.
In an accompanying editorial, also in JAMA, the authors point out that more than 80% of women who took estrogen as directed only used it for an average of 3.5 years. Their point is that the results don’t directly address the “balance of risk and benefits associated with longer term estrogen use.” They also point to a larger review of data that show duration is an important factor when it comes to breast cancer risk, especially among lean women. Additionally, they say that tamoxifen, which actually antagonizes estrogen, has been shown to reduce breast cancer by 50%, which has led the International Agency for Research on Cancer to “conclude that unopposed estrogen therapy and combination HRT are carcinogenic.”
Are you confused yet?
Both set of researchers say that the decision to use estrogen or not is one that should be made between a woman and her doctor. Don’t forget: study findings continue to contradict. They add that while “there may still be a role for short-term use of unopposed estrogen for treating some women with menopausal symptoms, this role may be vanishing as existing and emerging data continue to be better understood in terms” of patients.
My thoughts? Err on the side of caution. Always.Read More
A study presented at the esteemed San Antonio Breast Cancer Symposium last week has fanned the flames about the benefits versus risks of hormone replacement for menopausal symptoms. In this study, which ironically was pulled from the site press release highlights after experts questioned its merit, researchers did a reanalysis of data from the Women’s Health Initiative trial, the infamous 2002 study that was halted after Preempro was shown to increase breast cancer risk. Their findings? That women who had participated in the estrogen only arm of the study, had had benign breast disease, had had hysterectomies and had family histories of no breast cancer actually had significant reductions in breast cancer incidence. What’s more, 75% of women who did not have benign breast disease at the study’s start also had a reduced risk of developing breast cancer.
So, this is good news, right?
Well, estrogen alone can only be used by women who have had hysterectomies; estrogen plus progestin is used in women with intact uteri in order to avoid uterine cancer. This means that only a subset of women with menopausal symptoms are eligible to use estrogen alone. Moreover, as a physician blogger points out, the findings run counter to most data that show that estrogen use is actually associated with an increased risk of breast cancer. He also notes that abstracts that are accepted as posters at major medical meetings often have flawed or spotty data; in fact, in my years as a medical writer, I’ve often run across abstracts that ultimately disagree with published works.
The bottom line here is that despite the news, using estrogen alone to treat menopausal symptoms might only be an option for a very small percentage of women and may still place them at risk for cancer. At the end of the day, prescribing hormone replacement therapy continues to challenge the Hippocratic Oath: first do no harm.Read More
Ladies (and gents)…in this corner, weighing in with fear, loathing and disease-mongering, hormone replacement therapy (HRT). And in the other – weighing in as ‘snake oil,’ everything that “doesn’t work,” remains “unproven,” is “unsafe,” hasn’t been approved by the Food & Drug Administration, alternative strategies. Put up your dukes!
Sounds like a boxing match without a referee, eh?
Adding to the controversy are recent study findings showing that Pfizer’s Preempro (estrogen plus progestin) HRT may increase the risk of aggressive, invasive breast cancer and deaths from breast cancer in some women. In fact, the lines continue to be drawn between those who will fight for their hormones no matter what and individuals who believe that either greater regulation is needed or that hormones should be taken off the market altogether. It reminds me of the controversy over mammography, which has been not been proven to decrease breast cancer rates or improve survival. That’s a post for another day, although I encourage you to check out the posts that my friend Marya has written.
The argument against using the Women’s Health Initiative Study (WHI) data to demonstrate the dangers of HRT focuses on the small percentage of women enrolled in the original study who were in the age group (5o to 54 years) when women would be starting hormone therapy. Indeed, research shows that in addition to the type of progesterone added to estrogen, the time on hormone therapy can significantly influence health risks. Moreover, in the WHI, women who took estrogen only were not shown to have increased breast cancer risk (but a heck of a lot other increased risks – just look at the data). And yet, after the WHI hormone study was halted in 2002, substantial declines in the rates of breast cancer were noted in numerous countries, including Canada and the United States. Adding fodder, many pro-HRT experts argue that the alternatives – bioidenticals or complementary medicine – are unproven and downright unsafe.
In case you’ve not been reading this blog regularly, I believe the following and wrote it to a very passionate reader of HealthNewsReview Blog who felt that I was marginalizing women’s suffering:
For decades, women have been duped into believing that menopause is a disease that requires medical treatment, but at the same time, researchers have been unable to differentiate many of its symptoms from those of aging. Consequently, it’s imperative not only to ask what we are treating but why and how.
By all means, if you are comfortable with HRT and other treatments, go for it. But use them with eyes wide open and always examine the risks versus benefits. You might be surprised by what you learn. And how much we still don’t know.
I recently ran across the following statement with regards to the confusion:
“Some things don’t need to be healed; they just need to progress naturally.”
When you’re down for the count, sweating and flashing and swinging without a referee, the call about HRT can be a tough call to make. The good news? Menopause won’t kill you and symptoms do eventually go away. It is just one more of life’s transitions that we have to navigate. Just try to steer yourself towards informed choices and decisions and always, ask the hard questions. There are always those who ‘do,’ and those who ‘don’t.’ Just be sure you’re doing or not for the right reasons.
More bad news from the Women’s Health Initiative study and hormone replacement therapy (HRT, combined estrogen and progestin) front: not only does combined HRT appear to double the risk for breast cancer in some women, but these cancers are more invasive/agressive and more likely to lead to death.
The WHI findings have been repeatedly criticized by HRT advocates, who claim that the the women who were studied were not representative of the typical menopausal population, e.g. they were older and well past menopause at enrollment. So it is true that the potential benefits of HRT that might have been experienced by younger women were not explored. Indeed, time on hormones and the relationship between hormone use and how far into menopause a woman is can influence risk, as can the progestagen component. (If you want to read more about these specific factors, click on the links.) Nevertheless, what is also clear is that following the 2002 findings and the significant decline in HRT prescriptions, a substantial decrease in breast cancer rates were observed in both the US and Canada, so much so that the Canadian Cancer Society recently recommended that HRT be taken only as a last resort.
And the latest study findings?
In their continuing quest to determine insights into the risk-benefit ratio of HRT, researchers continued to follow and evaluate data from 83% (12,788) original trial participants. They found that HRT increased the incidence of invasive breast cancers by as much as 8% (compared with placebo), and that these cancers were also likelier to spread to the lymph nodes (24% of women taking HRT were found to have lymph node tumors compared to 16% of women taking placebo). Moreover, twice as many women on HRT died as the result of their cancer.
In an accompanying editorial, Dr. Peter Bach, a health outcomes researcher from Sloan-Kettering Medical Center in New York City, suggests that the latest study findings may only be the tip of the iceberg and that “it is possible that the increase in breast cancer deaths due to hormone therapy has been underestimated in the current study and that with longer follow-up, the deleterious effect will appear larger.” Additionally, he notes that “available data dictate caution in the current approach to hormone therapy, particularly because one of the lessons from the WHI is that physicians are ill-equipped to anticipate the effects of hormone therapy on long-term health.” Nor, have short-term approaches to hormone therapy been proven in clinical trials. As Dr. Bach points out, how can practitioners help patients make informed decisions if they are ill-informed themselves and the information, “speculative.” Nevertheless, the North American Menopause Society is taking the opposite stance, stating that ” clinicians can help women put the breast cancer risk into perspective by informing them that the increased risk of breast cancer using estrogen plus progestogen for 5 years is very similar to the increased risk of breast cancer associated with having menopause 5 years later. This increased risk of breast cancer occurs with a woman’s own internal, natural estrogen and progesterone.”
If this study and its accompanying editorial don’t raise a few flags, nothing will. And despite the pro-HRT stance of the North American Menopause Society, I encourage all women to start educating themselves before making the HRT leap. What’s more, be aware that once you start taking hormones, your practitioner might not be able to provide evidenced-based information on how to stop them, should you decide that they are not for you.
Ask yourselves, what is the trade-off here?
(Reuters Health, as usual, has a few more gems from this study that are required reading. You can find them here.)Read More