It has been known for a while that obesity can cause lymphedema, but is the inverse also true? Does lymphedema cause weight gain by encouraging the body to store fat? And what would that mean for prevention and management?
The gradual accumulation of excess fluid in a lymphedematous limb will, not surprisingly, gradually increase overall body weight. Conversely, better management of lymphedema will reduce swelling and decrease body weight. But what I want to talk about here is body fat. Clinical studies have long hinted at a complex relationship between lymphatic drainage and adipose tissue (fat deposits) but deconstructing this relationship has been difficult.
Fat is far more than just a place to store excess food energy
Adipose tissue is popularly imagined as inert blobs of lard: stashes of extra food energy collected from our diets for the purpose of fending off starvation or providing insulation against the cold. But the truth is that fat is a remarkably complex and active tissue. Adipose tissue is highly vascularized with blood and lymphatic vessels, and it produces and secretes a variety of hormones involved in energy metabolism and other bodily functions.
In other words, adipose tissue plays numerous important roles in daily life. However, when adipose tissue accumulates to high levels, such as in obesity, its architecture and behaviour poses unique challenges for the lymphatic system.
Excess adipose tissue exacerbates lymphedema and can initiate its onset
The fact that morbid obesity can induce irreversible lymphedema in otherwise normal individuals exposes a design flaw in human anatomy: while our bodies have a fantastical capacity to make and store fat, our vascular architecture is much more limited in its ability to handle the demands excess adipose tissue places on it.
The more fluid-rich adipose tissue you have, the more work your lymphatic system must do to drain the excess fluid (“interstitial fluid”) that is normally left behind by veins and collected by the lymphatic system. The lymphatic system must clear this fluid in order to maintain normal fluid levels and prevent swelling and lymph stagnation. But the lymphatic system has an upper limit on how much fluid it can handle.
Under normal conditions in healthy individuals the lymphatic system operates well below its functional capacity. This leaves a reserve capacity or “gas in the tank” that enables the lymphatic system to handle the exceptional fluid processing demands caused by a broken ankle, pregnancy, or some other swelling-inducing event.
The reserve capacity of the lymphatic system is on display in an obese individual. Despite what might be an enormous increase in body mass and resulting interstitial fluid, the lymphatic system can continue to maintain fluid balance – but only up to a point. At critically high levels of adipose tissue (BMI over 30 kg/m2), it is believed that the lymphatic system can become overloaded by a combination of excess fluid, physically compressed lymphatic vessels, and inflammation. These changes eventually culminate in obesity-induced lymphedema and irreversible damage to the lymphatic system.
But the relationship between lymphatic drainage and adipose tissue is also a two-way street. Not only can dangerously high levels of adipose tissue promote lymphedema, advanced lymphedema promotes abnormal adipose tissue development.
Late stage lymphedema will cause adipose tissue to accumulate in the affected limb
Unmanaged lymphedema is progressive, meaning that it will continue to worsen with time. Chronic swelling leads to further damage and greater swelling and inflammation. It also leads to tissue hardening caused by fibrosis (scarring) and the accumulation of new tissue, especially adipose tissue, which appears to be the result of abnormal stem cell behaviour. One study reported a 73% increase in adipose tissue in patients’ lymphedematous arms compared to their normal arms (ref 1).
So not only can advanced obesity cause lymphedema, advanced lymphedema can case fat to develop in the affected limb.
But does reduced lymphatic drainage encourage the body to store fat?
Advanced cases of lymphedema can cause considerable fibrosis and localized deposition of adipose tissue. But what about less advanced cases of lymphedema, or in people lymphatic drainage deficiencies but no noticeable swelling? Could changes in lymphatic drainage change the way the body metabolizes fat? A fascinating new study published in the International Journal of Obesity suggests that the answer to this question is “yes” (ref 2).
The researchers investigated two groups of premenopausal women with similar levels of body fat: a group with “normal” lymphatic drainage activity in their lower body (as assessed by lymphoscintigraphy) and a group with “worsened” lymphatic drainage activity. For the purposes of this study researchers excluded participants who had potentially confounding conditions such as venous insufficiency, cardiovascular disease, diabetes, cancer, metabolic disorders, obesity, and others. The women who displayed “worsened” lymphatic drainage also did not display overt signs of lymphedema and the volume of their lower limbs were the same as that of their “normal” peers. We can therefore say with good certainty that women with late stage lymphedema were not included in this study, and neither were women with lipedema.
The researches took these two groups of women and looked at how adipose tissue in their upper leg behaved when at rest and when stimulated with adrenaline, a hormone that encourages fat to break down to release energy. They found that women who had worsened lymphatic drainage displayed a lower “in vivo lipolytic index” as well as reduced “lipolytic responsiveness”. In other words, women who displayed worsened lymphatic drainage in their legs had fat stores that were less willing to break down and release energy both when at rest and in response to stimulation.
So does lymphedema cause weight gain by promoting fat? The unwillingness of adipose tissue to release stored energy is likely to be a good predictor of long-term weight gain in women (ref 3). Accordingly, the authors of this study hypothesized that reduced lymphatic drainage in the lower body could make fat deposits in the lower body more resistant to intentional weight loss.
What does this mean for lymphedema management?
This research suggests that even before overt swelling is present, diminished lymphatic drainage is causing changes in the interstitial fluid that bathes cells. These microenvironmental changes convince adipose cells to resist calls to break down fat deposits to release stored food energy.
While this may be the first report of fat metabolism being slowed by reduced lymphatic drainage, this finding is not without precedent. Patients with lipedema develop large and abnormal fat deposits in the lower body, and this process also appears to involve defective microcirculation. There is also evidence that mechanical massage (Endermologie ®) can increase the willingness of adipose tissue in the upper leg to breakdown fats, presumably by improving local microcirculation (ref 4).
We have already known that adipose tissue carries with it a high fluid burden, and at higher levels of adiposity inflammation and mechanical distortion of lymphatic vessels can occur. This has always provided good motivation for individuals with lymphedema to manage their body weight (lest they exacerbate their symptoms), and for obese individuals to work to reduce theirs (among other health reasons).
Now these new findings tell us something more. They suggest that even without overt swelling being present, weakened lymphatic drainage can cause subtle tissue changes that encourage the unnecessary storage of fat. For individuals with lymphedema, awareness of this cycle of lymphatic deficiency promoting fat, and vice versa, should reinforce the urgency with which they approach reducing uncontrolled swelling, and the necessity of good ongoing lymphedema management practices including regular self-massage.
So does lymphedema cause weight gain? Yes, in three ways: (1) uncontrolled lymphedema causes the accumulation of excess fluid, (2) advanced lymphedema (Stage II / II) causes abnormal fat to develop in the affected limb, and (3) weakened lymphatic drainage in otherwise healthy limbs encourages local adipose tissue to resist calls to breakdown fat.
- Brorson H., Ohlin K., et al. Breast cancer-related chronic arm lymphedema is associated with excess adipose and muscle tissue. Lymphat Res Biol. 2009; 7(1):3-10. abstract
- Valaliova Z., Vlasak R., et al. Lymphatic drainage affects lipolytic activity of femoral adipose tissue in women. Int J Obes (Lond). 2020 Mar 5. [Epub ahead of print] abstract
- Arner P., Andersson D.P., et al. Weight gain and impaired glucose metabolism in women are predicted by inefﬁcient subcutaneous fat cell lipolysis. Cell Metab. 2018 Jul3;28(1):45–54 e3. abstract
- Marques MA, Combes M, Roussel B, Vidal-Dupont L, Thalamas C, Lafontan M, et al. Impact of a mechanical massage on gene expression proﬁle and lipid mobilization in female gluteofemoral adipose tissue. Obes Facts. 2011;4(2):121–9. abstract