In addition to diet, other causes of elevated triglycerides are certain diseases, medications and estrogen replacement therapy, according to WebMD. It is uncommon for triglyceride levels to go up without an underlying explanation.
If diabetes is not controlled, triglycerides often rise, WebMD states. Hypothyroidism -- when the thyroid gland produces an insufficient amount of hormone -- is associated with excessive triglycerides. Kidney disease and some inherited lipid disorders, which also cause high cholesterol, affect triglycerides as well.
Several medications increase triglyceride levels, such as birth control pills, steroids and diuretics, which remove excess water from the body, reports WebMD. Patients with high blood pressure, heart failure or irregular heart rates use beta-blockers, and these bump up triglycerides. Tamoxifen, typically used in hormone therapy for breast cancer, produces the same result, as does estrogen replacement therapy for menopause symptoms.
Triglycerides are one kind of fat in the bloodstream, Mayo Clinic says. The body changes any unneeded calories a person consumes into triglycerides and stores them in fat cells to be used later for energy.
Maintaining healthy triglyceride levels is important because high amounts help lead to stroke, heart attack and heart disease. Too many triglycerides are responsible, in part, for hardening of the arteries and atherosclerosis, a thickening of arterial walls.