What Modern Science Is Discovering About Ancient Jewish Practices

For thousands of years, Jews have wrapped tefillin every weekday morning, paused to make a blessing before eating, and recited Shema before bed — not because we knew that these practices were good for us from a mental and physical health perspective, but simply because Hashem commanded us to do them.

We don’t need neuroscience and medicine to validate Torah, still it’s fascinating to see modern research uncover unexpected connections between Jewish practice and what we’re learning about the brain, the body, and human behavior. Here are a few examples.

Modeh Ani and Kriyat Shema al Hamitah

Judaism beautifully frames the day with gratitude in the morning and reflection at night. Before many Jews even put their feet on the floor, they recite Modeh Ani, thanking Hashem for returning their soul for another day and having abundant faith in them. Modern psychologists have found that gratitude and positive affirmations can improve mood, reduce anxiety, and help shape the mindset we carry into the rest of the day.

Before going to sleep, we recite Kriyat Shema al Hamitah, asking Hashem for protection, forgiving those who may have wronged us, reflecting on the day that has passed, and placing ourselves in His care. Researchers have long recognized the value of consistent bedtime routines for promoting better sleep and reducing stress. Kriyat Shema offers something even richer: a nightly opportunity to let go of the day before going to sleep.

Sources:

Cohen GL and Sherman DK. The Psychology of Change: self-affirmation and social psychological intervention. Annu Rev Psychology (2014); 65:333-71

Epton T and Harris PR. Self-affirmation promotes health behavior change. Health Psychology (2008); Nov 27 (6): 746-52.

Netilat Yadayim

One of the first rituals many Jews perform each morning is netilat yadayim. Before breakfast, before checking emails, and before the day fully begins, we wash each hand in an alternating pattern. No one has specifically studied netilat yadayim, but researchers have explored the effects of bilateral movement for years. Alternating, rhythmic movements have been associated with helping people feel calmer and more present. Whether or not the connection is intentional, it’s an interesting parallel to one of Judaism’s oldest daily rituals.

Source:

Amano, T., & Toichi, M. (2016). The Role of Alternating Bilateral Stimulation in Establishing Positive Cognition in Emotional Processing With EMDR Therapy: A Pilot Study. Frontiers in Psychology, 7, Article 1048. https://doi.org/10.3389/fpsyg.2016.01048

Tefillin

Putting on tefillin is one of Judaism’s most physical mitzvot. Every weekday morning, the straps are wrapped around the arm while prayers are recited, creating a ritual that engages both body and mind. Researchers at the University of Cincinnati recently examined the physiological effects of wearing tefillin and found measurable changes in heart rate variability and parasympathetic activity, both markers associated with relaxation and cardiovascular health. The researchers suggested that regularly wearing tefillin could even help reduce damage from certain types of heart attacks, though additional research is needed.

Jewish tradition has always viewed tefillin as something that shapes not only our actions but also our thoughts. In Jewish mysticism, the head tefillin symbolizes higher awareness and spiritual consciousness. Some contemporary writers have drawn parallels between its placement and the concept of the “third eye” or pineal gland. While those comparisons haven’t been established scientifically, they reflect the longstanding Jewish understanding that tefillin is meant to elevate both mind and spirit.

Source:

University of Cincinnati: “Study Shows Expanded Cardiovascular Benefits Wearing Tefillin Around the Arm in Both Men and Women”

Mikvah

The mitzvah of mikvah is often discussed in terms of ritual purity, but it also creates a unique rhythm within marriage. Jewish family life includes periods of physical separation followed by reunion after immersion in the mikvah. Researchers studying natural family planning found that couples who practiced periodic abstinence had significantly lower rates of divorce than couples using several other forms of family planning. The authors note that religiosity likely plays an important role, but they also suggest that the communication, anticipation, and intentional reconnection built into these rhythms may strengthen marital relationships.

Source:

Fehring & Manhart, “Natural Family Planning and Marital Chastity” (The Linacre Quarterly)

Fasting

Judaism includes several communal fast days throughout the year, each with its own purpose. Yom Kippur is devoted to repentance, while fasts like Tisha B’Av and the Seventeenth of Tammuz commemorate moments of national tragedy. Across them all, fasting shifts our attention away from physical comforts and toward spiritual reflection.

Modern medical research has explored fasting from a different perspective. Studies suggest it may improve insulin sensitivity and blood sugar regulation, reduce markers of inflammation, support heart health, and aid in weight management. Researchers are also investigating whether fasting could play a role in cancer prevention and treatment, though that research is still in its early stages.

Sources:

de Cabo R, Mattson MP. Effects of Intermittent Fasting on Health, Aging, and Disease. New England Journal of Medicine (2019).

Anton SD, et al. Flipping the Metabolic Switch: Understanding and Applying the Health Benefits of Fasting. Obesity (2018).

Patterson RE, Sears DD. Metabolic Effects of Intermittent Fasting. Annual Review of Nutrition (2017).

If you found this content meaningful and want to help further our mission through our Keter, Makom, and Tikun branches, please consider becoming a Change Maker today.