Written by Magnus
Is filtered water healthier than tap water and bottled water? What are the benefits of filtered water versus bottled water? What are the health concerns of bottled water?
We decided to compare the three and find a scientific answer to the questions. This study is based in Europe for simplicity, but it will also be valid in many other regions of the world.
This article is quite detailed. If you are not interested in the details, you can just read the conclusion at the end.
Nutrients in water
Before looking at individual sources of drinking water, it is important to understand the potential nutritional contribution of drinking water. Many people drink bottled water because they believe it may be healthier. But is it really?
In 2005, the WHO held a conference of experts from around the world to investigate. At the conference, information was shared from more than 80 epidemiological studies of varying quality over the past 50 years. The studies addressed the issue of hard water consumption, the impact of minerals on health and the possible reduction in the incidence of ischemic cardiovascular disease in populations.
Tap and bottled water supplies are highly variable in mineral content, and although some contribute appreciable amounts of certain minerals due to natural conditions (e.g., Ca, Mg, Se, F, Zn), intentional additions (F), or leaching from pipes (Cu), most provide smaller amounts of nutritionally essential minerals. With all these considerations in mind, the nutrients sometimes found in drinking water at potentially significant levels and of greatest concern are:
Calcium - important for bone health and possibly cardiovascular health.
Magnesium - important for bone and cardiovascular health
Fluoride - effective in preventing tooth decay
Sodium - an important extracellular electrolyte, lost under conditions of excessive sweating
Copper - important antioxidant function, iron utilization and cardiovascular health
Selenium - important in general antioxidant function and for the immune system
Potassium - is important for a variety of biochemical effects, but is not generally found in natural waters at significant levels.
The meeting concluded that:
1. The hard water benefit hypothesis was probably valid. That is, hard water
lasts having more minerals reduces cardiovascular diseases.
2. Magnesium was probably the most positive beneficiary.
Source: WHO Health Conference on Water Sanitation 2015
Bottled water
For the past 30 years, bottled water, and in particular the mineral water industry, has led us to believe that bottled water is the healthiest option. But is there any real evidence or proof of this?
According to European legislation (Directive 2009/54/EC), natural mineral waters are "sourced from an aquifer or an underground reservoir, are born from one or more natural springs or wells and have specific hygiene characteristics and, possibly, health properties".
Source: https://www.ncbi.nlm.nih.gov/m/pubmed/11318912/i=2&from=/19890742/related
What are the benefits of mineral water?
There are many studies specifically focused on showing the positive health benefits of certain minerals in bottled water. These include calcium, magnesium,
bicarbonate, chloride, iron, sulfate or combinations of these.
However, these studies confirmed that minerals themselves are healthy and not necessarily that mineral water is healthier than other waters. According to the above, tap water or also foods with these minerals provided the same health benefits.
Chloride - salt and vegetables
Bicarbonate - bread
Magnesium - black beans, spinach, bananas
Calcium - dairy, broccoli, almonds, kale
Potassium - banana, potato, broccoli, zucchini
Sulfate - eggs, garlic, broccoli, cabbage
Iron - spinach, broccoli, nuts, dried fruit
Source: https://www.healthline.com/nutrition
For regions where people do not have a varied diet of vegetables and fruits, the mineral content of drinking water could, however, make a difference, as the 2005 WHO Conference concluded.
What are the negative aspects of bottled water?
Many studies have also focused attention on the safety of mineral water.
bottled water, in particular the migration of chemicals from plastic containers into water, but also microplastics and microbial contaminants.
Plasticizers and DS's
Plasticizers (additives used to impart flexibility and handling properties to various types of plastics) and endocrine disruptors (EDs - chemicals that interfere with the functioning of the endocrine system) are the main compounds involved with adverse effects on human health.
One concern with bottled mineral water is the release of chemicals from the bottles into the water. For example, plasticizers such as Di(2-ethylhexyl) phthalate (DEHP) – widely used as a plasticizer and also present in PET bottles.
Source: Migration of phthalates from plastic products to model solutions. Coll
Anthropol. 2003;27 (Suppl 1):23-30.
SDs represent another important issue for bottled water. Some in vitro studies have investigated the exposure of chemicals with estrogen-like activity in bottled mineral water. Pinto et al. analyzed 30 samples of nine Italian mineral waters stored in PET bottles and the results show that 90% of the samples elicited an estrogenic activity less than 10% of the activity induced by the reference model. In contrast, the analysis of German mineral water stored in PET, glass and TetraPak bottles demonstrates a significantly elevated estrogenic activity in 12 of the 20 brands ( Ref ). In an updated study, bioanalytical techniques and in vivo experiments with a molluscan model are used to determine the estrogenicity of bottled water. The estrogenic activity of water bottled in PET containers is approximately twice that of products bottled in glass ( Ref ).
In addition, 29 glass and plastic bottles sold to consumers in southern Spain were tested by the University of Granada (Spain).
All water samples analyzed showed endocrine disrupting chemical (ED) hormonal activity. Estrogens at pollutant levels have been linked to breast cancer in women and prostate cancer in men. Estrogens also disrupt fish physiology and can affect reproductive development in both domestic and wild animals.
Sources:
Screening of estrogen-like activity of mineral water stored in PET bottles. Pinto B, Reali D. Int J Hyg Environ Health. 2009 Mar;212(2):228–32.
Environmental impact of estrogens on human, animal and plant life: A critical review, 2016.
Microplastics in bottled water
In addition to plasticizers and EDs, microplastics were found in 92% of all bottled water in Europe, according to tests of 250 bottles from 11 brands carried out by OrbMedia in 2018. The bottles contained an average of 314.6 plastic particles per liter. In a bottle, 10,000 plastic particles per 1 liter. For microplastic debris about 100 microns in size, about the diameter of a human hair, bottled water samples contained almost twice as many microplastic pieces per liter (10 ,4) than tap water samples (4.45).
Source: OrbMedia, March 15, 2018, Microplastics in Water Report
Bottled.
Investigation Details: CONTAMINATION OF SYNTHETIC POLYMERS IN BOTTLED WATER Sherri A. Mason, Victoria Welch, Joseph Neratko, State
University of New York at Fredonia, Department of Geology & Environmental Sciences March 14, 2018.
Microbial contaminants
Bottled and tap water can contain microbial contaminants. People with sensitive immune systems and/or weakened by conditions such as AIDS, chemotherapy, or transplant medications are more vulnerable to microbial contaminants in drinking water, such as Cryptosporidium. To prevent waterborne cryptosporidiosis, it is recommended to either boil drinking water for a full minute or use a point-of-use water filter.
Source: EPA Bottled Water Health Series 2005
Verdict: Mineral water is generally safe to drink, containing minerals with proven health benefits. On the other hand, most bottles contain microplastics and/or estrogenic residues that can pose a health risk.
Tap water
Forty years ago, few people questioned the quality of public tap water. We were advised to drink tap water in some places during short visits, as sensitive tummies might take time to adopt the local bacterial culture, but that was it. Since then, a growing interest in health, new research into water contaminants (e.g. nitrates, lead, biological disinfectants and microplastics) has changed everything.
People are right to be concerned and greater awareness of a fluid that we consume 2-3 litres of every day is a big deal. What’s not good is that too many people have given up healthy tap water for bottled water because of these concerns.
In fact, water regulation and treatment technologies have improved significantly during this period, and it is very likely that tap water quality is much better today. Examples of recent improvements include strict regulation, filtration and nitrate monitoring in Germany.
How healthy is tap water?
Assuming a daily water intake of 2-3 liters, water would provide >1% of the recommended intake for only four minerals; copper, 10%; calcium, 6%; magnesium, 5%; and sodium, 3%. At maximum concentration it would provide about 20% of Ca, 23% of Mg, 10% of Zn, and 33% of Na.
Source: USDA
Tap water can be a clinically significant source of magnesium, another essential mineral for the human body. Magnesium supports blood cell turnover and the immune system.
According to the "Journal of General Internal Medicine," a study published by researchers at McGill University in March 2001 stated that drinking 2 liters of tap water in some cities can meet between 6% and 18% of your recommended daily intake of calcium.
We also compared well-known brands of mineral water with tap water in Barcelona and concluded that tap water in Barcelona has a higher mineral content than almost all mineral water. This is generally true for cities with hard water.
Most water suppliers offer frequently updated water quality reports online, including minerals, contaminants and other substances. In Europe, a good starting point might be the EU water directives by country.
What are the risks of tap water?
Drinking water is supplied through 7 million kilometres of pipes across Europe. Many of these pipes were laid in the early to mid-20th century and have a lifespan of 75-100 years. We would need to double our sector's annual investment of €45 billion to modernise our infrastructure and protect health, the environment and, at least to some extent, reduce costs.
Sources:
What is the risk with lead in tap water?
In 2009 it was estimated that 25% of households in the EU have a lead pipe, either as a connection to the water main, as part of the internal plumbing, or both, potentially putting 120 million people at risk from lead in drinking water within the EU.
In 2016, the American Academy of Pediatrics issued Prevention of Childhood Lead Toxicity, outlining the scope of childhood lead exposure, its health impacts, and management guidelines. The report states that there is no safe level of lead in the blood.
Sources:
Is lead still a problem in Europe? Dec 2009
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4824718/
Chlorination issues
Published reports have shown an increased risk of colorectal cancers in people exposed to chlorinated drinking water or chlorination chemicals. There is also inconclusive evidence from observational studies that disinfection byproducts (DBPs) in drinking water are associated with colorectal cancer.
Source: https://academic.oup.com/ije/article/39/3/733/628142
This meta-analysis of the best available epidemiological data indicates that long-term consumption of chlorinated drinking water is associated with bladder cancer, particularly in men.
Source: https://www.ncbi.nlm.nih.gov/m/pubmed/12594192/
A 2012 opinion from the American College of Obstetricians and Gynecologists Committee on Lead Screening During Pregnancy and Lactation outlines the available evidence related to lead exposure and maternal and fetal health. Although the opinion does not recommend routine blood lead testing for all pregnant women, it does recommend measures for pregnant and lactating women whose blood levels exceed certain thresholds.
This review showed that several meta-analyses and pooled analyses found a statistically significant excess risk for some indicators of exposure to chlorinated water or trihalomethanes and bladder and colorectal cancer, small for gestational age, stillbirth, all congenital anomalies combined, and ventricular septal defects, but no statistically significant excess risk for many other congenital anomalies. The excess risk was generally small but robust, with little sensitivity to individual study results or evidence of publication bias.
Source: https://pubs.acs.org/doi/abs/10.1021/bk-2010-1048.ch024
Pharmacists
Over the past 10 years, there have been frequent warnings about pharmaceuticals, and birth control pills in particular. While the risk from birth control pills in particular has been dismissed, there are other pharmaceutical residues to be concerned about. Animal production appears to be responsible for over 90% of the estrogen found in the environment and water supplies, including some bottled water. The remaining 10% appears to come from industrial chemicals commonly used in manufacturing (such as BPA) and synthetic estrogens in fertilizers spread on crops.
On the other hand, recent studies have concluded that the most similar tap water estrogen poses a small risk compared to other sources such as milk at 150x.
Sources:
Birth Control Hormones in Water: Separating Myth from Fact
MDPI: Pharmaceuticals in the Built and Natural Water Environment of the United States
An Assessment of Potential Exposure and Risk of Estrogens in Drinking Water
Microplastics
OrbMedia’s research recently found that 83% of water samples collected across five continents tested positive for microplastics (Europe 74%). We don’t yet know what the health risk is, but it’s likely to be negative.
Source: OrbMedia September 2017
Verdict: Public tap water is generally safe to drink. Some tap water also has the same amount of minerals as the most mineral-rich bottled water. However, as with mineral water, there are risks from well-known contaminants such as lead, chlorine bi-products and new ones such as microplastics and pharmaceuticals.
Filtered tap water
Home water filters are nothing new, but recent advances have made the filtration process better, filters easier to install and use, reduced costs and greatly improved sustainability. This means that having a water filter installed at home is now feasible for every household in Europe. So, is filtered water healthier and what are the benefits of filtered water?
The choice of water filter will have a big impact on the quality of your water. In some cases, filtered water can be worse than tap water due to bacteria growth in the filter or the removal of all minerals. Choose a filter that suits your needs in terms of installation, contaminant removal, filtered volume and cost. Always make sure it is a reputable brand and that the filters have been independently tested according to international standards such as NSF.
The most common water filters today are activated carbon filters with or without ion exchange, including pitchers/carafes, tap filters, gravity filters, reverse osmosis, refrigerator filters, UV light and distillation. Generally the best value for money and sufficient filtration for Europe is a tap filter with carbon block (also referred to as PAC Filter or Charcoal Filter).
Is filtered water healthier?
As outlined in this paper, both tap and bottled water face major challenges with contamination and aging infrastructures. Some of these issues, such as microplastics, will take decades to resolve. Therefore, point-of-use filters that remove or greatly reduce such contaminants can reduce the risk of contamination and thus improve the health of individual households.
A recent study also concluded that “activated carbon-based tap water filters could provide an important short-term public health benefit through the removal of halogenated DBPs, but regular replacement of filter cartridges is critical to maintaining good filter effectiveness.”
Source:
Negative aspects of filter water
Some filters, such as reverse osmosis, remove all the good and bad content from the water. This means that there are no minerals left after the filtration process. With a varied diet, this probably doesn't matter.
Another challenge is when filters unintentionally make tap water worse over time.
A recent study of Point of Use (PoU) reverse osmosis water filters revealed widespread bacterial contamination in the treatment devices. Other studies have come to similar conclusions. The use of reverse osmosis filters is only advisable if the devices are consistently and carefully maintained.
Sources:
This also applies to activated carbon filters, which trap but do not kill bacteria. Since the filter cannot kill bacteria, it can actually become a breeding ground for microorganisms if not changed regularly. An old, unused PoU filter can be dangerous because using it can add bacteria, which had been killed at the tap by chlorine, back into the water. As long as filters are changed according to the instructions, this risk is minimal.
Similar tests carried out by a laboratory in Germany found that 24 of 34 filters tested had increased bacteria counts. 4 out of 6 had a higher bacteria count after 7 weeks than tap water.
Sources:
University of Berkeley on December 6, 2000
Verdict: A quality, fit-for-purpose water filter will vastly reduce the risk of contaminants in tap water and is therefore likely to be healthier than both tap water and bottled water. The wrong or poorly maintained water filter could, however, increase the risk.
Conclusion - bottled, filtered or tap water?
All three types of water, including bottled mineral water, tap water and filtered water, are generally safe to drink in Europe. Therefore, the choice is really to eliminate the risks and thus improve long-term health prospects. Total elimination of risk is impossible, and because it is so difficult to measure risk, safety is really a matter of managing risk to a reasonable degree, not trying to eliminate it altogether. Safety and the absence of risk are different things.
Here is our attempt to classify each type
|
Bottled water |
Tap water |
Filtered water |
|
|
Minerals |
Low to high Depends on the bottle |
Low to high Depends on location |
Zero to high Depends on filter type |
|
Contaminants |
Medium risk |
Medium risk |
Very low risk |
In conclusion, filtered water is healthier. A quality water filter that is independently tested for the type of tap water in your household will reduce the risk and therefore likely have long-term health benefits.
Comments, questions or feedback. Please comment below or write to us at natasha@tappwater.pt