Karen Rose Dietzen

Karen Rose (Mertens) Dietzen, aged 76, passed away peacefully into the hands of God on March 23, 2026, in the presence of her family. Her Funeral Mass is Friday April 17, 10:00a.m. at the St. Francis of Assisi Catholic Church in Sacramento, California where she was a devoted and active parishioner for 22 years.

Karen lived an active life full of faith, love, learning, and adventure. She was born in Spokane, Washington on September 3, 1949, just minutes after her identical twin, Sharon Witte. She spent her early years in Spokane until the family relocated to Lexington, Kentucky where she graduated from Lexington Catholic High School in 1967. She obtained a Bachelor of Science degree in nursing from the University of Kentucky through the NROTC Navy Nurse Program. She then served in the Navy from 1971-1973 at Oak Knoll Naval Hospital, in Oakland, California where she met the late Sanford (Sandy) Dietzen. Her time in the Navy brought her across seas and sparked a lifelong passion for travel. She retired as a Captain and after marrying Sandy, the couple relocated to Eastern Washington where they had four children: Fredrick, Thadeus, Rebecca and Elizabeth. The family relocated to Stockton, California in 1981. While her kids were very young, Karen also managed to complete her Master of Arts degree in Marriage and Family Counseling from the University of San Francisco.

Karen found her professional life-passion in supporting nursing moms and babies. She served many years as a La Leche League (LLL) leader and was an early and strong advocate for increasing education for medical professionals and access for all families. Many of her lifelong friendships began with her LLL and breastfeeding connections. She worked as a nurse in Stockton area hospitals, and after becoming one of the first ever International Board Certified Lactation Consultants, ran a business renting hospital grade breast pumps to nursing mothers and providing private consultations. She also served on local taskforces to improve hospital conditions for nursing mothers and babies, even traveling to China on a baby-friendly delegation. For many years, she pursued her breastfeeding advocacy through county and state public health work. During this time, she met her longtime partner, James (Jim) Kesey. They shared a passion for classical music, crossword puzzles, delicious food (made by Karen) and even a few years in a softball league together. In 2002, she secured her dream job working as the first ever postpartum lactation consultant at the University of California Davis Medical Center, helping new mothers learn the art of breastfeeding. Karen’s knowledge and passion benefitted many, including her sisters, nieces and the mothers of her grandchildren, to whom she provided this advice freely. In 2010, she was honored by Medela with a lifetime achievement award for breastfeeding support and advocacy.

Upon retirement from UC Davis, Karen kept busy helping with and loving her grandchildren, Isaac and Eleanor Andrews, Eliza, Declan and Theo Dietzen, James and David Dietzen, and Anderson, Sydney and Alexander Olsen. Her home was the center of festivities for major holidays and birthdays. She also served as lector coordinator, delivered Communion at Mass and to home-bound parishers at St. Francis of Assisi Catholic Church. She loved to travel and visited an impressive amount of countries, including: China, Australia, New Zealand, Poland, the Czech Republic, Guatemala, Chile, South Africa, Zambia, Zimbabwe, Kenya, Tanzania, Uganda, Israel, Thailand, Hong Kong, Vietnam, Cambodia, France, Spain, Italy, and Sicily. She even planned to take each of her grandchildren who reached the age of 15 on a trip of a lifetime; the four children who were lucky enough to take this trip chose London, Paris (x2!), and Australia.

Her love of learning extended to a continued presence in a Spanish language group. More important than the Spanish, however, was the deep and lasting friendships she forged with the other women in the course. She loved canning, and her apricot jam was unmatched. Her physical activities included walking, water aerobics, and Tai Chi (another group of women whom she was deeply connected with through friendship). The many friends she made in her active life visited her at Mercy General Hospital in the final days of her life, doing Tai Chi, speaking Spanish, bringing Holy Communion, and thanking her for all the cookies she baked and gave to her neighbors. The medical team commented on the love and support they saw for Karen from her friends and family.

Karen was preceded in death by her parents, Theordore James Mertens and Mona Ann (Derr) Mertens, her partner of 26 years, James Kesey, her oldest brother Theodore Mertens, Jr., and her son-in-law Wesley Andrews. She is survived by her four children, Fredrick Dietzen, Thadeus Dietzen, Rebecca Dietzen and Elizabeth Dietzen Olsen (Dan Olsen), 10 grandchildren and her twin sister Sharon Witte (Laguna Hills, CA), Donna Mertens (Rockville MD), Theresa Uthe (Ft. Wright KY), Carolyn Ludeman (Lake Oswego OR), Mark Mertens (Portland OR), Mary Mertens James (Salem OR), Paul Mertens (Stanwood WA), John Mertens (Phoenix AZ), Daniel Mertens (Wilmington NC), and Frederick Mertens (Bothell WA), as well as several nieces and nephews throughout the country.

On top of her professional contributions, Karen’s life serves as a shining example of living the Holy Gospel, speaking up for those without voices, advocating for mothers and babies to have the strongest possible start and serving those most in need, including the homeless population in Sacramento. She shared this gift with her grandchildren, taking them with her on these outings to lead by example by treating the less fortunate with humanity and respect. Her family and community will miss her love, warmth, smiles, candor and willingness to be present for others.

In lieu of flowers, donations may be made in Karen’s honor to St. Francis of Assisi’s Outreach Ministry, which includes Mercy Peddlers, that supports the poor and homeless and more than anything, Karen would appreciate us carrying on her work of direct services to the unhoused community.